The optical vignetting effect exists in most optical imaging systems, which seriously affects the imaging quality. How to effectively improve the optical vignetting effect is the key point in the design of aerospace optical remote sensors. A radiometric calibration method was used to quantify the influence of the optical vignetting effect in the imaging system and to obtain the correction coefficients. The correction coefficients were optimized by polynomial fitting method, and the correction system was reduced by about three orders of magnitude after fitting, which greatly reduced the demand for storage resources of the embedded system. The polynomial fitting method effectively reduced the correction coefficients and improved the optical vignetting effect. The non-niformity error of the camera before correction is 13.2%, and after correction, the non-uniformity error is reduced to 3.8%, which meets the requirements of general imaging systems for response non-uniformity. The method is suitable for implementation in FPGA-based processors with fewer correction coefficients, high real-time performance and low resource consumption, and has practical engineering value.