Thank you (@Christiaan Conover) for your reply, but the new website will be different in (categories, tags, new pages, new menu) that's what i mean by completely new, so i'm not upgrading or migrating.
But in the other side i need to use all the content from the old WP site ( the data itself as a raw martial e.g: if i have 1000 post i need to use them in my new site, i don't need to enter them again instead reuse them)
I hope that i make it more clear.
Thanks