diff --git a/rucaptcha.gemspec b/rucaptcha.gemspec
index ff50488..4ff80a5 100644
--- a/rucaptcha.gemspec
+++ b/rucaptcha.gemspec
@@ -16,7 +16,7 @@ Gem::Specification.new do |s|
   s.homepage              = 'https://github.com/huacnlee/rucaptcha'
   s.require_paths         = ['lib']
   s.extensions            = %w[ext/rucaptcha/extconf.rb]
-  s.summary               = 'This is a Captcha gem for Rails Application. It run ImageMagick command to draw Captcha image.'
+  s.summary               = 'This is a Captcha gem for Rails Applications. It drawing captcha image with C code so it no dependencies.'
   s.license               = "MIT"
   s.required_ruby_version = ">= 2.0.0"