Abstract: The intelligent public telephone system platform is composed of three sub-platforms including the voice connection, digital running and value-added services. The system combines PSTN with IP network in order to supply varied value-added services for intelligent public telephone. The system adopts the idea of softswitch which separates the calling control from service carrying. The value-added services platform can increase new value-added services through service providers' interface at any time to meet public requirements of new services. Expounding the design and implementation of intelligent public telephone system, the performance of the system is analyzed.