Modulation transfer function (MTF) plays an important role in the CCD camera imaging system. It indicates the relation between spatial frequency and image contrast. In the MTF measurement experiment, the choosing of the test board is the key. The measurement accuracy of the system and the complexity of operating procedure strongly depend on it. Although the ideal function of the test board is sine function, it is difficult to make up the sine test board. In order to solve this problem, the testing method of MTF is introduced, in which the sine test board is replaced by the resolving power test target consisting of parallel dark and bright stripes alternately. The MTF of CCD camera is examined at the Nyquist frequency and the results are analyzed and evaluated in detail.