In consideration of the exposure precision of a curtain shutter and the dimension of a camera, a new focus-plane single curtain type shutter was designed by using a timing belt with high transmission accuracy as the curtain of shutter and a belt wheel as the roll shaft. The main reason effecting the exposure precision was analyzed, and a mathematic model was created by the system error synthesis method. Then, the series of gear-composited errors was used to evaluate the transmission errors of a driving mechanism. Furthermore, the geometric model of the polygonal effect was established by analysis of the transmission mechanism of the timing belt, and the influence of polygonal effect on the rate errors was calculated. After testing on the shutter,the speed stability of the roll shaft is obtained and the exposure precision achieves 0.067 according to the Gaussian processes. The exposure time at 5 positions on a frame was tested by the photoelectric method,and the result shows that exposure precision in the frame achieves by 0.056, which demonstrates that this shutter can exposure on the aerial photographing of large range illuminance.