A scalable authentication protocol based on bilinear paring was proposed. There are several advantages of the new protocol: (1) By using the bilinear group, the length of public parameter and keys decreases with the same security level, hence we reduce bandwidth needed in communication, thus the protocol is more suitable for the huge internet system. (2) It incorporates a 3-factor authentication mechanism for detecting compromise. (3) The password can be canceled by user's requirement. (4) The protocol has great efficiency and scalable implement.