This paper concludes the technique and application character of USSD, the related network structure of USSD platform, explains the handle flow of the interactive response of USSD. By analyzing the application type in mobile communication and market benefit of USSD, combining the feature of USSD service platform, it presents the infrastructure of USSD system and application, including composing of core system, deployment of application (assignment of service code, suitable application type and market benefit), and the influence and change to the existent network.