With the continuous development of digital television transmission technology and the rapid popularization of intelligent terminals, the form of digital television tends to be diversified. Considering the advantages and disadvantages of traditional IP network television, cable television and radio television and in order to overcome the shortcomings of traditional TV transmission system, the use of IP network transmission mode ,this paper designed and realized a multiscreen interactive system based on terrestrial digital broadcasting television (DTMB). Through the combination of terrestrial broadcasting network and broadband IP network, the terrestrial digital TV signal through IP network multicast transmission to the intelligent terminal equipment, can effectively reduce the consumption of network resources, while ensuring that multiple intelligent devices at the same time watch TV programs. Firstly, introduced the system hardware block diagram and the main chip that the system involved in. Then, described the design of demodulation software, the realization of IP over TS and the design flow of client software in detail. Finally, summarized the application scene of the system.