diff --git a/docs/ckb-core-dev.md b/docs/ckb-core-dev.md
index 3a645aca99..2517f4e108 100644
--- a/docs/ckb-core-dev.md
+++ b/docs/ckb-core-dev.md
@@ -25,7 +25,7 @@ cd test && cargo run ../target/debug/ckb
 
 ## Chain Spec
 
-The subcommand `ckb init` has an option `--export-spec` to export spec files
+The subcommand `ckb init` has an option `--export-specs` to export spec files
 as well, which allows editing the chain spec for development.
 
 The chain spec can switch between different PoW engines. Wiki has the [instructions](https://github.com/nervosnetwork/ckb/wiki/PoW-Engines) about how to configure it.-
diff --git a/src/setup/cli.rs b/src/setup/cli.rs
index 5b6df9da1f..76862021f4 100644
--- a/src/setup/cli.rs
+++ b/src/setup/cli.rs
@@ -149,6 +149,7 @@ fn init() -> App<'static, 'static> {
         .arg(
             Arg::with_name(ARG_EXPORT_SPECS)
                 .long(ARG_EXPORT_SPECS)
+                .hidden(true)
                 .help("Export spec files as well"),
         )
 }