A service subscription method is provided. The method includes the following steps. A service subscription request is received from a client. The request carries a service identifier (ID). Service information about a service that the client requests to subscribe to and information about related services of the service that the client requests to subscribe to are obtained according to the service ID. Related-service-set subscription information is obtained according to the information about the service to be subscribed to and the information about its related services. The related-service-set subscription information is returned to the client. Moreover, a service subscription system and server are also provided. Through the technical solutions of the present invention, the interaction process of related-service subscription is simplified and the system resources are saved, and the real-time performance of service subscription and the probability of related-service subscription are also increased.