A method for authenticating network access of a terminal, comprising: sending, by the terminal, a user identity authentication request to an authentication server, wherein the user identity authentication request comprises first authentication information and second authentication information, the first authentication information is used by the authentication server to authenticate a user identity of the terminal, and the second authentication information is used by the authentication server to determine a platform corresponding to the terminal; after receiving user identity authentication acknowledgment information sent by the authentication server, sending, by the terminal, a platform identity authentication request to the authentication server, wherein the platform identity authentication request comprises third authentication information; and receiving, by the terminal, platform identity authentication acknowledgment information sent by the authentication server, wherein the platform identity authentication acknowledgment information is sent after the authentication server determines, based on the second authentication information and the third authentication information, that a platform corresponding to the platform identity authentication request is consistent with a platform corresponding to the second authentication information; wherein the first authentication information comprises a user identity authentication certificate, the second authentication information comprises identity authentication certificate information of the platform corresponding to the terminal, and the third authentication information comprises identity authentication certificate information of the platform corresponding to the terminal; wherein the identity authentication certificate information of the platform is used by the authentication server to determine an identity authentication certificate of the platform corresponding to the terminal; and the user identity authentication request further comprises a first plaintext and a first ciphertext obtained by encrypting the first plaintext by using a private key for the identity authentication certificate of the platform corresponding to the terminal, the first plaintext is used to match a second plaintext, and the second plaintext is a plaintext obtained by decrypting the first ciphertext by using a public key in a platform identity authentication certificate determined based on the second authentication information. sending, by the terminal, a user identity authentication request to an authentication server, wherein the user identity authentication request comprises first authentication information and second authentication information, the first authentication information is used by the authentication server to authenticate a user identity of the terminal, and the second authentication information is used by the authentication server to determine a platform corresponding to the terminal; after receiving user identity authentication acknowledgment information sent by the authentication server, sending, by the terminal, a platform identity authentication request to the authentication server, wherein the platform identity authentication request comprises third authentication information; and receiving, by the terminal, platform identity authentication acknowledgment information sent by the authentication server, wherein the platform identity authentication acknowledgment information is sent after the authentication server determines, based on the second authentication information and the third authentication information, that a platform corresponding to the platform identity authentication request is consistent with a platform corresponding to the second authentication information; wherein the first authentication information comprises a user identity authentication certificate, the second authentication information comprises identity authentication certificate information of the platform corresponding to the terminal, and the third authentication information comprises identity authentication certificate information of the platform corresponding to the terminal; wherein the identity authentication certificate information of the platform is used by the authentication server to determine an identity authentication certificate of the platform corresponding to the terminal; and the user identity authentication request further comprises a first plaintext and a first ciphertext obtained by encrypting the first plaintext by using a private key for the identity authentication certificate of the platform corresponding to the terminal, the first plaintext is used to match a second plaintext, and the second plaintext is a plaintext obtained by decrypting the first ciphertext by using a public key in a platform identity authentication certificate determined based on the second authentication information.