diff --git a/README.md b/README.md
index faf4974..c2b860f 100644
--- a/README.md
+++ b/README.md
@@ -27,8 +27,8 @@ Add `bucket`, `aws_key` and `aws_secret` to `deploy` in `_config.yml`.
 deploy:
   type: s3
   bucket: <S3 bucket>
-  aws_key: <AWS id key>
-  aws_secret: <AWS secret key>
+  aws_key: <AWS id key> //Optional, if the environment variable `AWS_KEY` is set
+  aws_secret: <AWS secret key> //Optional, if the environment variable `AWS_SECRET` is set
   concurrency: <number of connections> //Optional
   region: <region> //Optional, see https://github.com/LearnBoost/knox#region
 ```
diff --git a/index.js b/index.js
index cf4e801..cfeea47 100644
--- a/index.js
+++ b/index.js
@@ -10,6 +10,9 @@ var public_dir = hexo.config.public_dir || './public';
 hexo.extend.deployer.register('s3', function (args, callback) {
   var config = hexo.config.deploy;
 
+  config.aws_key = config.aws_key || process.env.AWS_KEY;
+  config.aws_secret = config.aws_secret || process.env.AWS_SECRET;
+
   if (!config.bucket || !config.aws_key || !config.aws_secret){
     var help = [
       'You should configure deployment settings in _config.yml first!',
@@ -18,8 +21,8 @@ hexo.extend.deployer.register('s3', function (args, callback) {
       '  deploy:',
       '    type: s3',
       '    bucket: <bucket>',
-      '    aws_key: <aws_key>',
-      '    aws_secret: <aws_secret>',
+      '    [aws_key]: <aws_key>        # Optional, if provided as environment variable',
+      '    [aws_secret]: <aws_secret>  # Optional, if provided as environment variable',
       '    [concurrency]: <concurrency>',
       '    [region]: <region>          # See https://github.com/LearnBoost/knox#region',
       '',
@@ -30,7 +33,6 @@ hexo.extend.deployer.register('s3', function (args, callback) {
     return callback();
   }
 
-
   var files = readdirp({
       root: public_dir,
       entryType: 'both'