diff --git a/README-zh.md b/README-zh.md
index a03053d1..f8369cad 100755
--- a/README-zh.md
+++ b/README-zh.md
@@ -124,6 +124,8 @@ chmod +x bin/spc
 ./bin/spc doctor
 # 拉取所有依赖库
 ./bin/spc fetch --all
+# 只拉取编译指定扩展需要的所有依赖
+./bin/spc download --by-extensions=openssl,pcntl,mbstring,pdo_sqlite
 # 构建包含 bcmath,openssl,tokenizer,sqlite3,pdo_sqlite,ftp,curl 扩展的 php-cli 和 micro.sfx
 ./bin/spc build "bcmath,openssl,tokenizer,sqlite3,pdo_sqlite,ftp,curl" --build-cli --build-micro
 ```
diff --git a/README.md b/README.md
index 3bd471fc..6f58e82f 100755
--- a/README.md
+++ b/README.md
@@ -133,7 +133,9 @@ Basic usage for building php and micro with some extensions:
 # Check system tool dependencies, fix them automatically
 ./bin/spc doctor
 # fetch all libraries
-./bin/spc fetch --all
+./bin/spc download --all
+# only fetch necessary sources by needed extensions
+./bin/spc download --by-extensions=openssl,pcntl,mbstring,pdo_sqlite
 # with bcmath,openssl,tokenizer,sqlite3,pdo_sqlite,ftp,curl extension, build both CLI and phpmicro SAPI
 ./bin/spc build bcmath,openssl,tokenizer,sqlite3,pdo_sqlite,ftp,curl --build-cli --build-micro
 ```