A method and system for performing services in a server and a client of a client/server architecture are provided, and the method includes: when performing to a preset user decision point during the service performing process, the server interrupting the service performing and initiating a user decision request to a client, wherein the user decision request includes information requesting the user to decide a service performing action after the user decision point; after a user decision information made by the client responding to the user decision request is received, determining the service performing action corresponding to the received user decision information according to the corresponding relationship between the user decision information and a service performing rule, and performing the service according to the determined service performing action. The service performing action or flow can be intervened or influenced by the client through the present invention.