The present invention discloses a method for implementing high rate packet data (HRPD) service authentication, said method can be used in the multimode network including IS95/CDMA2000 IX and CDMA 2000 HRPD network. Said method includes the following steps: user terminal (AT) uses the user information in the user identification module (UIM) as user identity identification, starting to make authentication of extended authentication protocol (EAP); mobile switching centre (MSC)/visit location register (VLR) can obtain random number and first authentication number according to said user identify identification; according to described random number AT can calculate second authentication number, MSC/VLR can compare first authentication number with second authentication numbers, if they are identical, the authentication is successful, otherwise the authentication is failure. |