diff --git a/CHANGELOG.md b/CHANGELOG.md
index b5bc7ae..480a441 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 ## Change Log
 
+### v0.3.5
+
+- Fix the issue that StreamWriter will read more bytes than wanted
+
 ### v0.3.4
 
 - Fix handling gzip/deflate response
diff --git a/lib/aliyun/oss/http.rb b/lib/aliyun/oss/http.rb
index 4fe2496..79271b8 100644
--- a/lib/aliyun/oss/http.rb
+++ b/lib/aliyun/oss/http.rb
@@ -52,8 +52,13 @@ def read(bytes = nil, outbuf = nil)
           ret = ""
           loop do
             if bytes
-              ret << @buffer.slice!(0, bytes)
-              break if ret.size >= bytes
+              fail if bytes < 0
+              piece = @buffer.slice!(0, bytes)
+              if piece
+                ret << piece
+                bytes -= piece.size
+                break if bytes == 0
+              end
             else
               ret << @buffer
               @buffer.clear
diff --git a/lib/aliyun/version.rb b/lib/aliyun/version.rb
index 046e387..39f855e 100644
--- a/lib/aliyun/version.rb
+++ b/lib/aliyun/version.rb
@@ -2,6 +2,6 @@
 
 module Aliyun
 
-    VERSION = "0.3.4"
+    VERSION = "0.3.5"
 
 end # Aliyun
diff --git a/spec/aliyun/oss/http_spec.rb b/spec/aliyun/oss/http_spec.rb
index 923e764..4452f21 100644
--- a/spec/aliyun/oss/http_spec.rb
+++ b/spec/aliyun/oss/http_spec.rb
@@ -58,6 +58,24 @@ module OSS
           r = s.read
           expect(r).to eq('')
         end
+
+        it "should read exactly bytes" do
+          s = HTTP::StreamWriter.new do |sr|
+            100.times { sr << 'x' * 10 }
+          end
+
+          r = s.read(11)
+          expect(r.size).to eq(11)
+
+          r = s.read(25)
+          expect(r.size).to eq(25)
+
+          r = s.read(900)
+          expect(r.size).to eq(900)
+
+          r = s.read(1000)
+          expect(r.size).to eq(64)
+        end
       end # StreamWriter
 
     end # HTTP