The site selection of large scale information system test is the key issue in test preparation. It relates the success or failure of the test. Traditional site selection has many disadvantages, such as low efficiency and unreliability. This paper raises a test site selection method based on digital elevation model. Compared with traditional method, this method has the advantages of high efficiency and reliability. The site selection criteria are established by analytic hierarchy process. And the criteria are used to analyze the digital elevation model to identify suitable sites. This paper verifies the validity of the method through site selection in an information system test.