To determine the relationship between the size parameters and the exposure accuracy of a curtain-type shutter,the expression of exposure time is calculated,and the mathematical model of exposure accuracy is established according to the principle of the curtain-type shutter and its exposure time. Then,the main factors impacting the exposure time accuracy are analysed,and the error for every parameter is calculated with an error synthesized method.Finally,by taking an aerocamera as an example,the exposure accuracy is worked out. The experiment results indicate that the slit width on the curtain-type shutter is proportional to exposure time between 1/1 000~1/100 s,and the exposure time accuracy is increased with the slit width. The minimum exposure time accuracy of the shutter in the camera is 6.4%,which is higher than the accuracy of 8.59% calculated by the theory. The error influenced by the slit width is 3.6 times that influenced by the velocity.