Based on geometry optical, the numerical simulation model of segmented telescope system with ray tracing is built, and the relation between curvature radius error of individual mirrors of segmented primary mirror and the image quality of segmented telescope system are analyzed. As monoliphic primary mirror, the error of curvature radius primary can be compensated by adjusting the focus of telescope system, but wavefront aberration induce by the random error of curvature radius of segmented primary mirror cannot be compensated and should zoom the wavefront aberration. When cophased the segmented primary mirror (wipe off the piston and tip-tilt induce by error of curvature radius of individual mirror), the image quality of segmented telescope system will be improved and the effect of error of curvature radius of individual mirror will be reduced.