This paper begins with an introduction of Machine Translation,including what is MT,its importance,the approaches applied in MT and the translating process.Then the discussion is switched to Chinese-English MT and the difficulties in analytical and transformational phases.Difficulty in dealing with tense and aspect is among the toughest tasks in CEMT,which is the focus of study in the present research.The thesis gives a full discussion of the time system im Chinese and its differences with that in English before it carries out a thorough analysis of the auxiliary wordzhewith the help of corpus study.Finally this paper proposes some algorithms to deal with different cases of zhein CEMT,shedding some lights on how to solve the linguistic problem of tense and aspect from computational linguistics point of view in CEMT.