diff --git a/README.md b/README.md
index 74c1b02..ad4de43 100644
--- a/README.md
+++ b/README.md
@@ -186,6 +186,17 @@ You can log additional data between span start and finish. For example, `annotat
 $span->annotate('Order Validated')
 ```
 
+### PercentageSampler
+
+Use `PercentageSampler` to control the upload of samples according to the sampling rate and reduce data reporting
+
+- Adding configuration to `.env`,Reporting rate `0 ~ 1`, `0.2` 20% data reporting
+- ZIPKIN_SAMPLER_CLASS support `"Zipkin\\Samplers\\BinarySampler"`、`"Zipkin\\Samplers\\PercentageSampler"` `"Zipkin\\Samplers\\BinarySampler"` representative upload all
+```bash
+ZIPKIN_SAMPLER_CLASS="Zipkin\\Samplers\\PercentageSampler"
+ZIPKIN_PERCENTAGE_SAMPLER_RATE=0.2
+```
+
 ## Flushing Spans
 
 Flush refers to the process of sending all pending spans to the transport. It will also reset the state of the tracer including the active spans and UUID:
diff --git a/config/tracing.php b/config/tracing.php
index 9a365e4..26f7d60 100644
--- a/config/tracing.php
+++ b/config/tracing.php
@@ -1,5 +1,7 @@
 <?php
 
+use Zipkin\Samplers\BinarySampler;
+
 return [
 
     /*
@@ -97,7 +99,7 @@
             'max_tag_len' => 1048576,
             'request_timeout' => 5,
         ],
-        'sampler_class' => \Zipkin\Samplers\BinarySampler::class,
+        'sampler_class' => env('ZIPKIN_SAMPLER_CLASS', BinarySampler::class),
         'percentage_sampler_rate' => env('ZIPKIN_PERCENTAGE_SAMPLER_RATE', 0.2),
     ],