I want change my Apple ID Password, but ask me 2 questions and i forget the answer of this questions and when i want reset security questions i have this message : we donot have sufficient information to reset your serurity questions.

 contact Apple ID Support.

Apple ID Support

Apple ID Support (2) 

Apple Support by e-mail or chat    Work through the screens to get a chat option. 

Apple Support using Twitter

Or fill out and submit this form.          The form is for iTunes, but it will get passed to the ID Support section.  

From the article below. 

Without proof of your identity via security questions and other carefully selected criteria, Apple Support can't help you reset a password or perform any other actions on your account. These policies are audited and reviewed on a regular basis.

Security and your Apple ID