During the answering process of Computerized Adaptive Testing, if the item hasn’t exposed or the exposure rate is low, the construction cost of Examination Question Bank will be consequently lost. Conversely, if the item exposure rate is too high, it may seriously damage the security of question bank. Therefore, during the test, if the item exposure rate is not controlled properly, the advantages of Computerized Adaptive Testing would become pointless. This research not only proposes eight kinds of item exposure control methods in the knowledge structure based adaptive testing but also estimates the effects of these eight methods. Research findings demonstrate that each one of these item exposure control methods can respectively attain good effects among various indicators. As a result, the examiner could, based on the dimensions of his or her emphasis, select a suitable exposure control method when needed.