diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5f8790525ed7e..ccf01fdd66428 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -70,6 +70,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 ### Deprecated
 
 ### Removed
+- Remove some unused code in the search backpressure package ([#15518](https://github.com/opensearch-project/OpenSearch/pull/15518))
 
 ### Fixed
 - Fix constraint bug which allows more primary shards than average primary shards per index ([#14908](https://github.com/opensearch-project/OpenSearch/pull/14908))
diff --git a/server/src/main/java/org/opensearch/search/backpressure/SearchBackpressureService.java b/server/src/main/java/org/opensearch/search/backpressure/SearchBackpressureService.java
index 1261711221925..e04a56ad4c84f 100644
--- a/server/src/main/java/org/opensearch/search/backpressure/SearchBackpressureService.java
+++ b/server/src/main/java/org/opensearch/search/backpressure/SearchBackpressureService.java
@@ -80,7 +80,6 @@ public class SearchBackpressureService extends AbstractLifecycleComponent implem
     private final SearchBackpressureSettings settings;
     private final TaskResourceTrackingService taskResourceTrackingService;
     private final ThreadPool threadPool;
-    private final LongSupplier timeNanosSupplier;
 
     private final NodeDuressTrackers nodeDuressTrackers;
     private final Map<Class<? extends SearchBackpressureTask>, TaskResourceUsageTrackers> taskTrackers;
@@ -150,7 +149,6 @@ public SearchBackpressureService(
         this.taskResourceTrackingService = taskResourceTrackingService;
         this.taskResourceTrackingService.addTaskCompletionListener(this);
         this.threadPool = threadPool;
-        this.timeNanosSupplier = timeNanosSupplier;
         this.nodeDuressTrackers = nodeDuressTrackers;
         this.taskManager = taskManager;
 
diff --git a/server/src/main/java/org/opensearch/search/backpressure/settings/SearchShardTaskSettings.java b/server/src/main/java/org/opensearch/search/backpressure/settings/SearchShardTaskSettings.java
index 105023a20173f..6d016c7466362 100644
--- a/server/src/main/java/org/opensearch/search/backpressure/settings/SearchShardTaskSettings.java
+++ b/server/src/main/java/org/opensearch/search/backpressure/settings/SearchShardTaskSettings.java
@@ -26,12 +26,8 @@
  */
 public class SearchShardTaskSettings {
     private final List<CancellationSettingsListener> listeners = new ArrayList<>();
-    private final ClusterSettings clusterSettings;
 
     private static class Defaults {
-        private static final double CANCELLATION_RATIO = 0.1;
-        private static final double CANCELLATION_RATE = 0.003;
-        private static final double CANCELLATION_BURST = 10.0;
         private static final double TOTAL_HEAP_PERCENT_THRESHOLD = 0.05;
         private static final long CPU_TIME_MILLIS_THRESHOLD = 15000;
         private static final long ELAPSED_TIME_MILLIS_THRESHOLD = 30000;
@@ -165,7 +161,6 @@ public SearchShardTaskSettings(Settings settings, ClusterSettings clusterSetting
         this.cancellationRatio = SETTING_CANCELLATION_RATIO.get(settings);
         this.cancellationRate = SETTING_CANCELLATION_RATE.get(settings);
         this.cancellationBurst = SETTING_CANCELLATION_BURST.get(settings);
-        this.clusterSettings = clusterSettings;
 
         clusterSettings.addSettingsUpdateConsumer(SETTING_TOTAL_HEAP_PERCENT_THRESHOLD, this::setTotalHeapPercentThreshold);
         clusterSettings.addSettingsUpdateConsumer(SETTING_CPU_TIME_MILLIS_THRESHOLD, this::setCpuTimeMillisThreshold);
diff --git a/server/src/main/java/org/opensearch/search/backpressure/settings/SearchTaskSettings.java b/server/src/main/java/org/opensearch/search/backpressure/settings/SearchTaskSettings.java
index 4b12eda9fb59d..4b34323b1ddc6 100644
--- a/server/src/main/java/org/opensearch/search/backpressure/settings/SearchTaskSettings.java
+++ b/server/src/main/java/org/opensearch/search/backpressure/settings/SearchTaskSettings.java
@@ -27,7 +27,6 @@
 
 public class SearchTaskSettings {
     private final List<CancellationSettingsListener> listeners = new ArrayList<>();
-    private final ClusterSettings clusterSettings;
 
     private static class Defaults {
         private static final double CANCELLATION_RATIO = 0.1;
@@ -166,7 +165,6 @@ public SearchTaskSettings(Settings settings, ClusterSettings clusterSettings) {
         this.cancellationRatio = SETTING_CANCELLATION_RATIO.get(settings);
         this.cancellationRate = SETTING_CANCELLATION_RATE.get(settings);
         this.cancellationBurst = SETTING_CANCELLATION_BURST.get(settings);
-        this.clusterSettings = clusterSettings;
 
         clusterSettings.addSettingsUpdateConsumer(SETTING_TOTAL_HEAP_PERCENT_THRESHOLD, this::setTotalHeapPercentThreshold);
         clusterSettings.addSettingsUpdateConsumer(SETTING_CPU_TIME_MILLIS_THRESHOLD, this::setCpuTimeMillisThreshold);