To ensure the real-time performance of the nonuniformity correction of the complementary metal-oxide-semiconductor (CMOS) image sensor in aerospace remote sensing cameras and reduce the photo response non-uniformity (PRNU) of the image, according to the structural characteristics of the CMOS image sensor, a CMOS image non-uniformity correction method based on an adaptive moving window is proposed in this study. First, from the perspective of engineering applications, a movable variable-step window is used to block the image so that multiple columns of pixels in the same window shared a set of correction parameters. Then, to solve the problem of insufficient linear fitting correction accuracy in existing methods, based on the nonlinear response characteristics of the CMOS sensor, the response curve is second-ordered by the least squares method. Experimental results show that the method can not only improve the quality of CMOS images but also reduce the number of correction parameters of the hardware system. The PRNU of the image corrected by the method is less than 1%. Compared with the linear fitting correction method, the number of correction parameters of the method is reduced by 23.7%.