If I want to show same font in all browser, including old browsers (example: IE6, Opera9 etc.)
which one should I choose @font-face or Web-font or both? Also I want to know Which One loads faster?
Web-font is just a tool designed to make @font-face usage easier.
I'd say just use @font-face. The less external resources you have (such as web-fonts), the less you have to worry about going wrong.