Abstract: This paper reviews the theory of the Hidden Markov Model(HMM)and the speech recogIlition system. By using the embedded platform, the manned-spacecrar speech recognition system is built based on the HMM technology. To meet complex requirements of future spacecraft for speech recognition, the specifications and rules for the speech recognition are optimized, with an improvement of the accuracy rate over the traditional voice activity detection algorithm. The application of this continous speech recognition system on manned-spacecraft shows good results for the fhnction implementation of command sending and character input.