Cloud computing is a syncretic development result of traditional computer technology and network technology, whose core idea is to manage and attemper huge computing resources linked by network and then provide services for users from computing resources pool. The birth and speedy development of cloud computing bring new opportunities to test realm, which is closely related to computer technology. This paper discusses the requirement of applying cloud computing to test from three aspects such as hardware test, software test and automatic test system, then presents an automatic test system architecture based on cloud computing. At last, the paper presents the expectation and the obstacle of applying cloud computing to test.