CCD image sensor plays an important role as major solid-state array in scientific imaging application for its excellent performance. Generally speaking, some important parameters of CCD imager, such as transfer efficiency, readout noise and so on, should be firstly measured to estimate whether the imager can satisfy the performance requirements of whole system, especially in the scientific application. So it is very important to make research on the evaluation method of CCD imager. The paper introduces evaluation method of some important CCD parameter, including gain, readout noise, charge transfer efficiency, linearity, and well capacity. The methods to measure charge transfer efficiency by Fe55 X-ray source and extended pixel edge reaction are mainly discussed. Several ways to evaluate CCD gain are also analyzed in detail. A platform to evaluate CCD imager in the laboratory is developed and measurement tests of E2V CCD203_82 are also carried out using this method. The experiments show that the evaluation method we developed is feasible, flexible, and reliable.