A payment authentication method, the method comprising: receiving, by an onboard terminal, a payment authentication request sent by a server; forwarding the payment authentication request to a user device, the payment authentication request including a user identifier, wherein the user device has established a communication with the onboard terminal; receiving encrypted payment certification information responded by the user device, the encrypted payment certification information not being input into the user device by a user; sending the encrypted payment certification information to the server, the encrypted payment certification information including the user identifier and a user device identifier; receiving a certification result sent by the server; and performing payment processing according to the certification result, wherein the certification result indicates whether there is a binding relationship between the user identifier and the user device identifier; characterised in that, to establish the binding relationship between the user device identifier and the user identifier: acquiring (Sill) the user device identifier at the onboard terminal; encrypting the user device identifier and the user identifier with a public key of the server pre-stored in the onboard terminal; and sending the encrypted user device identifier and the encrypted user identifier to the server; and after establishing the binding relationship between the user device identifier and the user identifier, generating, at the server, a private key certificate according to the user device identifier and the user identifier; encrypting the private key certificate at the server; and sending, from the server, the encrypted private key certificate to the onboard terminal to allow payment processing; wherein the encrypted payment certification information is obtained by the user device by encrypting payment certification information using a private key certificate stored in the user device, and wherein after receiving the encrypted payment certification information, the server decrypts the encrypted payment certification information using a public key of the private key certificate stored in the server. receiving, by an onboard terminal, a payment authentication request sent by a server; forwarding the payment authentication request to a user device, the payment authentication request including a user identifier, wherein the user device has established a communication with the onboard terminal; receiving encrypted payment certification information responded by the user device, the encrypted payment certification information not being input into the user device by a user; sending the encrypted payment certification information to the server, the encrypted payment certification information including the user identifier and a user device identifier; receiving a certification result sent by the server; and performing payment processing according to the certification result, wherein the certification result indicates whether there is a binding relationship between the user identifier and the user device identifier; characterised in that, to establish the binding relationship between the user device identifier and the user identifier: acquiring (Sill) the user device identifier at the onboard terminal; encrypting the user device identifier and the user identifier with a public key of the server pre-stored in the onboard terminal; and sending the encrypted user device identifier and the encrypted user identifier to the server; and acquiring (Sill) the user device identifier at the onboard terminal; encrypting the user device identifier and the user identifier with a public key of the server pre-stored in the onboard terminal; and sending the encrypted user device identifier and the encrypted user identifier to the server; and after establishing the binding relationship between the user device identifier and the user identifier, generating, at the server, a private key certificate according to the user device identifier and the user identifier; encrypting the private key certificate at the server; and sending, from the server, the encrypted private key certificate to the onboard terminal to allow payment processing; generating, at the server, a private key certificate according to the user device identifier and the user identifier; encrypting the private key certificate at the server; and sending, from the server, the encrypted private key certificate to the onboard terminal to allow payment processing; wherein the encrypted payment certification information is obtained by the user device by encrypting payment certification information using a private key certificate stored in the user device, and wherein after receiving the encrypted payment certification information, the server decrypts the encrypted payment certification information using a public key of the private key certificate stored in the server.