diff --git a/docs/multi-thread-compression.txt b/docs/multi-thread-compression.txt
index d429963cb04462d3f734a7dfd529178dbf6e858d..26107478cb1ccda54ec13b202db08c3ff84d99b1 100644
--- a/docs/multi-thread-compression.txt
+++ b/docs/multi-thread-compression.txt
@@ -41,7 +41,7 @@ compression ratio. High compression ratio will take more time,
 level 1 stands for the best compression speed, and higher level means higher
 compression ration. For Zlib, users can select a level number between 0 and 9,
 where level 0 stands for no compression. For Zstd, users can select a
-level number between 1 and 22.
+level number between 1 and 19.
 
 
 When to use the multiple thread compression in live migration