diff --git a/doc/ss-local.asciidoc b/doc/ss-local.asciidoc
index 457467e8..9c481cf8 100644
--- a/doc/ss-local.asciidoc
+++ b/doc/ss-local.asciidoc
@@ -8,7 +8,7 @@ ss-local - shadowsocks client as socks5 proxy, libev port
 SYNOPSIS
 --------
 *ss-local*
- [-Auv] [-h|--help]
+ [-Auv6] [-h|--help]
  [-s <server_host>] [-p <server_port>] [-l <local_port>]
  [-k <password>] [-m <encrypt_method>] [-f <pid_file>]
  [-t <timeout>] [-c <config_file>] [-i <interface>]
@@ -96,6 +96,9 @@ Enable UDP relay and disable TCP relay.
 -A::
 Enable onetime authentication.
 
+-6::
+Resovle hostname to IPv6 address first.
+
 --fast-open::
 Enable TCP fast open.
 +
diff --git a/doc/ss-redir.asciidoc b/doc/ss-redir.asciidoc
index 6637f7f0..5993ceaf 100644
--- a/doc/ss-redir.asciidoc
+++ b/doc/ss-redir.asciidoc
@@ -8,7 +8,7 @@ ss-redir - shadowsocks client as transparent proxy, libev port
 SYNOPSIS
 --------
 *ss-redir*
- [-AuUv] [-h|--help]
+ [-AuUv6] [-h|--help]
  [-s <server_host>] [-p <server_port>] [-l <local_port>]
  [-k <password>] [-m <encrypt_method>] [-f <pid_file>]
  [-t <timeout>] [-c <config_file>] [-b <local_address>]
@@ -90,6 +90,9 @@ Enable UDP relay and disable TCP relay.
 -A::
 Enable onetime authentication.
 
+-6::
+Resovle hostname to IPv6 address first.
+
 --mtu <MTU>::
 Specify the MTU of your network interface.
 
diff --git a/doc/ss-tunnel.asciidoc b/doc/ss-tunnel.asciidoc
index 3979b19e..d8505d46 100644
--- a/doc/ss-tunnel.asciidoc
+++ b/doc/ss-tunnel.asciidoc
@@ -8,7 +8,7 @@ ss-tunnel - shadowsocks tools for local port forwarding, libev port
 SYNOPSIS
 --------
 *ss-tunnel*
- [-AuUv] [-h|--help]
+ [-AuUv6] [-h|--help]
  [-s <server_host>] [-p <server_port>] [-l <local_port>]
  [-k <password>] [-m <encrypt_method>] [-f <pid_file>]
  [-t <timeout>] [-c <config_file>] [-i <interface>]
@@ -96,6 +96,9 @@ Enable UDP relay and disable TCP relay.
 -A::
 Enable onetime authentication.
 
+-6::
+Resovle hostname to IPv6 address first.
+
 -L <addr:port>::
 Specify destination server address and port for local port forwarding.
 +