diff --git a/app/src/main/java/com/casic/app/safetreecontroller/extensions/LineChart.kt b/app/src/main/java/com/casic/app/safetreecontroller/extensions/LineChart.kt
index 1500877..e092200 100644
--- a/app/src/main/java/com/casic/app/safetreecontroller/extensions/LineChart.kt
+++ b/app/src/main/java/com/casic/app/safetreecontroller/extensions/LineChart.kt
@@ -1,12 +1,15 @@
 package com.casic.app.safetreecontroller.extensions
 
 import android.graphics.Color
+import android.graphics.Paint
+import com.casic.app.safetreecontroller.utils.LocaleConstant
 import com.github.mikephil.charting.animation.Easing
 import com.github.mikephil.charting.charts.Chart
 import com.github.mikephil.charting.charts.LineChart
+import com.github.mikephil.charting.components.LimitLine
 import com.github.mikephil.charting.components.XAxis
-import com.github.mikephil.charting.components.YAxis
 import com.pengxh.kt.lite.extensions.dp2px
+import com.pengxh.kt.lite.utils.SaveKeyValues
 
 fun LineChart.initConfig() {
     this.setNoDataText("无数据，无法绘制浓度趋势...")
@@ -22,14 +25,30 @@
     //去掉图例
     this.legend.isEnabled = false
     this.animateY(1200, Easing.EaseInOutQuad)
-    //设置样式
-    val rightAxis: YAxis = this.axisRight
+
     //设置图表右边的y轴禁用
-    rightAxis.isEnabled = false
-    val leftAxis: YAxis = this.axisLeft
-    leftAxis.axisMinimum = 0f
-    leftAxis.setDrawGridLines(false) //设置x轴上每个点对应的线
-    leftAxis.setDrawZeroLine(true)
+    this.axisRight.isEnabled = false
+    this.axisLeft.axisMinimum = 0f
+    this.axisLeft.setDrawGridLines(false) //设置x轴上每个点对应的线
+    this.axisLeft.setDrawZeroLine(true)
+    //添加限制线
+    val threshold = SaveKeyValues.getValue(LocaleConstant.METHANE_DEFAULT_VALUE_KEY, 1.99f) as Float
+    val limitLine = LimitLine(threshold, "阈值：${threshold}% VOL")
+    limitLine.lineWidth = 1f
+    limitLine.lineColor = Color.RED
+    //允许在虚线模式下绘制(线段长度，分隔长度，偏移量)
+    limitLine.enableDashedLine(10f, 10f, 0f)
+    //设置限制线标签的位置
+    limitLine.labelPosition = LimitLine.LimitLabelPosition.RIGHT_TOP
+    limitLine.textSize = 10f
+    limitLine.textStyle = Paint.Style.FILL
+    //添加限制线
+    this.axisLeft.addLimitLine(limitLine)
+    //只显示一条阈值线
+    if (this.axisLeft.limitLines.size > 1) {
+        this.axisLeft.limitLines.removeAt(0)
+    }
+    limitLine.isEnabled = true
 
     //设置x轴
     val xAxis: XAxis = this.xAxis
@@ -39,4 +58,23 @@
     xAxis.setDrawGridLines(false) //设置x轴上每个点对应的线
     xAxis.granularity = 1f //禁止放大后x轴标签重绘
     xAxis.position = XAxis.XAxisPosition.BOTTOM
+}
+
+fun LineChart.updateLimitLine(threshold: Float) {
+    val limitLine = LimitLine(threshold, "阈值：${threshold}% VOL")
+    limitLine.lineWidth = 1f
+    limitLine.lineColor = Color.RED
+    //允许在虚线模式下绘制(线段长度，分隔长度，偏移量)
+    limitLine.enableDashedLine(10f, 10f, 0f)
+    //设置限制线标签的位置
+    limitLine.labelPosition = LimitLine.LimitLabelPosition.RIGHT_TOP
+    limitLine.textSize = 10f
+    limitLine.textStyle = Paint.Style.FILL
+    //添加限制线
+    this.axisLeft.addLimitLine(limitLine)
+    //只显示一条阈值线
+    if (this.axisLeft.limitLines.size > 1) {
+        this.axisLeft.limitLines.removeAt(0)
+    }
+    limitLine.isEnabled = true
 }
\ No newline at end of file

diff --git a/app/src/main/java/com/casic/app/safetreecontroller/extensions/LineChart.kt b/app/src/main/java/com/casic/app/safetreecontroller/extensions/LineChart.kt
index 1500877..e092200 100644
--- a/app/src/main/java/com/casic/app/safetreecontroller/extensions/LineChart.kt
+++ b/app/src/main/java/com/casic/app/safetreecontroller/extensions/LineChart.kt
@@ -1,12 +1,15 @@
 package com.casic.app.safetreecontroller.extensions
 
 import android.graphics.Color
+import android.graphics.Paint
+import com.casic.app.safetreecontroller.utils.LocaleConstant
 import com.github.mikephil.charting.animation.Easing
 import com.github.mikephil.charting.charts.Chart
 import com.github.mikephil.charting.charts.LineChart
+import com.github.mikephil.charting.components.LimitLine
 import com.github.mikephil.charting.components.XAxis
-import com.github.mikephil.charting.components.YAxis
 import com.pengxh.kt.lite.extensions.dp2px
+import com.pengxh.kt.lite.utils.SaveKeyValues
 
 fun LineChart.initConfig() {
     this.setNoDataText("无数据，无法绘制浓度趋势...")
@@ -22,14 +25,30 @@
     //去掉图例
     this.legend.isEnabled = false
     this.animateY(1200, Easing.EaseInOutQuad)
-    //设置样式
-    val rightAxis: YAxis = this.axisRight
+
     //设置图表右边的y轴禁用
-    rightAxis.isEnabled = false
-    val leftAxis: YAxis = this.axisLeft
-    leftAxis.axisMinimum = 0f
-    leftAxis.setDrawGridLines(false) //设置x轴上每个点对应的线
-    leftAxis.setDrawZeroLine(true)
+    this.axisRight.isEnabled = false
+    this.axisLeft.axisMinimum = 0f
+    this.axisLeft.setDrawGridLines(false) //设置x轴上每个点对应的线
+    this.axisLeft.setDrawZeroLine(true)
+    //添加限制线
+    val threshold = SaveKeyValues.getValue(LocaleConstant.METHANE_DEFAULT_VALUE_KEY, 1.99f) as Float
+    val limitLine = LimitLine(threshold, "阈值：${threshold}% VOL")
+    limitLine.lineWidth = 1f
+    limitLine.lineColor = Color.RED
+    //允许在虚线模式下绘制(线段长度，分隔长度，偏移量)
+    limitLine.enableDashedLine(10f, 10f, 0f)
+    //设置限制线标签的位置
+    limitLine.labelPosition = LimitLine.LimitLabelPosition.RIGHT_TOP
+    limitLine.textSize = 10f
+    limitLine.textStyle = Paint.Style.FILL
+    //添加限制线
+    this.axisLeft.addLimitLine(limitLine)
+    //只显示一条阈值线
+    if (this.axisLeft.limitLines.size > 1) {
+        this.axisLeft.limitLines.removeAt(0)
+    }
+    limitLine.isEnabled = true
 
     //设置x轴
     val xAxis: XAxis = this.xAxis
@@ -39,4 +58,23 @@
     xAxis.setDrawGridLines(false) //设置x轴上每个点对应的线
     xAxis.granularity = 1f //禁止放大后x轴标签重绘
     xAxis.position = XAxis.XAxisPosition.BOTTOM
+}
+
+fun LineChart.updateLimitLine(threshold: Float) {
+    val limitLine = LimitLine(threshold, "阈值：${threshold}% VOL")
+    limitLine.lineWidth = 1f
+    limitLine.lineColor = Color.RED
+    //允许在虚线模式下绘制(线段长度，分隔长度，偏移量)
+    limitLine.enableDashedLine(10f, 10f, 0f)
+    //设置限制线标签的位置
+    limitLine.labelPosition = LimitLine.LimitLabelPosition.RIGHT_TOP
+    limitLine.textSize = 10f
+    limitLine.textStyle = Paint.Style.FILL
+    //添加限制线
+    this.axisLeft.addLimitLine(limitLine)
+    //只显示一条阈值线
+    if (this.axisLeft.limitLines.size > 1) {
+        this.axisLeft.limitLines.removeAt(0)
+    }
+    limitLine.isEnabled = true
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/casic/app/safetreecontroller/fragments/MethaneMonitorFragment.kt b/app/src/main/java/com/casic/app/safetreecontroller/fragments/MethaneMonitorFragment.kt
index e3548dc..51ea481 100644
--- a/app/src/main/java/com/casic/app/safetreecontroller/fragments/MethaneMonitorFragment.kt
+++ b/app/src/main/java/com/casic/app/safetreecontroller/fragments/MethaneMonitorFragment.kt
@@ -11,6 +11,7 @@
 import com.casic.app.safetreecontroller.R
 import com.casic.app.safetreecontroller.databinding.FragmentMethaneMonitorBinding
 import com.casic.app.safetreecontroller.extensions.initConfig
+import com.casic.app.safetreecontroller.extensions.updateLimitLine
 import com.casic.app.safetreecontroller.service.SocketConnectionService
 import com.casic.app.safetreecontroller.utils.LocaleConstant
 import com.casic.app.safetreecontroller.widgets.LineChartMarkerView
@@ -114,6 +115,7 @@
                 return@setOnClickListener
             }
 
+            binding.lineChart.updateLimitLine(threshold)
             SaveKeyValues.putValue(LocaleConstant.METHANE_DEFAULT_VALUE_KEY, threshold)
             val weakReferenceHandler = SocketConnectionService.weakReferenceHandler
                 ?: return@setOnClickListener