This paper describes an English conversation and pronunciation CAI using speech recognition techniques. This system was intended to recognize user's utterances and to respond to him properly according to the recognized results. In the case of a learner with unskilled pronunciation, because of differences in the phonemic system between his mother tongue and the second language, the speech recognition system cannot run normally. After this improvement, evaluation experiments were conducted. The results indicate that learners' ability in speaking and in listening to English is improved by using the system.