Through the study of bus technology，memory database technology，and virtual instrument technology，a new architecture of message bus based testing system is proposed to reduce the resource of testing equipment，and the cost of testing system. The core technology is using message bus instead of traditional testing bus，and using virtual instrument instead of hardware. The specific implementation is that gathering signal by computer standard bus based data acquisition card；processing，analyzing the data and illustrating the result by virtual instrument；and operating virtual instrument by message bus. The message bus based testing system architecture is characterized by low cost，strong extension and high system integration. Finally，the feasibility of the system architecture is proved by a testing application.