The focusing mechanism is an important guarantee to acquire remote sensing images for space camera. Synchronous accuracy on both ends of the focal plane is difficult to be eliminated, and it will affect sensing images. So synchronous accuracy analysis of double cam focusing mechanism and screw female focusing mechanism is important. First, it introduces working principle of two types of focusing mechanism, and then analyzes the sources of the synchronous error on both ends of the focal plane of two types of focusing mechanism, in the end, the synchronous accuracy of two types of focusing mechanism is tested. The calculation results show that the error of synchronous motion on both ends of the focal plane of two types by Statistical Method and Monte Carlo Method. Test results accord with the results of calculation. And the maximum error of synchronism is 20μm, the focusing mechanism of two types meets the requirements of practical application quite well.