The invention discloses a service authentication method, a service authentication system and a server. The method comprises the following steps that the server generates a link address which can be linked to an access position when receiving a service request from a user, and transmits the generated link address to a terminal corresponding to a terminal identifier preset by the user, namely a legal terminal; the server performs service authentication by judging whether a terminal initiating a first link request is a legal terminal or not after receiving the first link request initiated through a first link address. According to the method, the system and the server, even though the link address transmitted to the legal terminal by the server is illegally stolen, as long as the legal terminal is in a secure state and is not illegally used, the server can identify that a terminal linked to the local through the link address is not a legal terminal, and the service request cannot pass authentication, so that the service authentication reliability is improved.