The Hartmann-Shack(H-S) wavefront sensor is the most popular type in adaptive optics system operated with faint object, because of its outstanding advantages in high light efficiency, simple structure and large capacity of channels. The characters and accuracy of ICCD and CCD type H-S wavefront sensors operated with faint objects is deeply analyzed and compared. The algorithm for quantitative analysis is derived, and the experimental results are presented as well. All of these are useful for selection of technical scheme and engineering design of this kind of wavefront sensor operated with faint object.