Which method I can use high poly mesh bake to low poly ?
Cage method ???
That depends; Baking is complicated,
There is a great Course here on CGCookie on Baking in Blender: https://cgcookie.com/courses/bake-texture-baking-with-blender
As Martin says, it's too broad of a question. It'll depend on so many things. You can check out the course, and if you have questions on something that is giving you trouble, we're here to help you get out of the woods.
