Abstract: A client instant information service system and method is disclosed. The invention is a utility that can be operated with different OSs. The client/user only needs to execute one signal action to complete a given operation through the UOI (User Operating Interface) provided by the invention. The invention can also perform content updating, downloading, and browsing by instantly informing the client/user of any change on the server to achieve the purpose of real-time information/data transmission. The disclosed method includes the steps of: calling the interface generation module to generate user interfaces by the procedure control unit, calling the operation response module based on input messages of the client/user, calling the real-time data module to perform procedures and receiving an EXIT request from the client/user.