Abstract: The Methods was proposed based on the analysis of Modulation Transfer Function(MTF) test error of spaceborne TDI CCD camera, the influence from grating period error, environment vibration and imaging noise was retained from MTF testing. The MTF testing is affected by grating period error, environment vibration and imaging noise. Through analyzing the influence mechanism, a mathematic module was established to describe the influence of grating period error, environment vibration and imaging noise. The correcting algorithm of the testing MTF error from grating period error was proposed, and the optimization mask of MTF testing was also proposed to reduce the influence from image noise. Based on the testing images, the horizontal scale of MTF mask should not exceed 4% of the Morie fringe horizontal period, the vertical scale of MTF mask should not exceed 2% of the Morie fringe vertical period. The analysis shows that if the mask is larger, the influence from noise is reduced, but the influences from the environment vibration and grating period error will increase. In the real project, the mask scale should be selected based on the imaging system noise level, and ensure the accuracy of the MTF testing.