diff --git a/src/config.rs b/src/config.rs
index 36def66..e59085d 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -21,6 +21,7 @@ use parking_lot::Mutex;
 /// ```
 pub struct Config {
     /// Each appender is responsible for printing its own business
+    /// every LogAppender have one thread(need Mutex) access this.
     pub appends: SyncVec<Mutex<Box<dyn LogAppender>>>,
     /// the log level filter
     pub level: LevelFilter,