Multithread technology is becoming widely popular. Video decoding based on multi-threading has important research value and use value, it will achieve high improvement in decoding speed. This paper introduces the impletmentation of multithread programming in Mcrosoft Windows. Applying the multithreading technique in JEPG2000 video decoding, the image datas could be processed parallelly, and the decoding speed will be increased. The experiment results show that, system with binuclear, tetranuclear and eight kernels improves the decoding speed by two times, four times and eight times, respectively, compared to system with mononuclear. The Multi-threading technique improves the efficiency of program running by making full use of the resources of multi-core computer.