The CCD response characteristic of the multi-spectral imaging system was analyzed, and the physical model was proposed as a new method of linearization. Based on the analysis of the linear correction principle and method of the digital camera CCD response value, it was compared with the traditional model such as polynomial model and the exponential model in two aspects of the correction accuracy and spectral reconstruction effect. Experimental results show that the linear correlation of each channel after linear correction was further enhanced, and in the GOG model the channel correlation coefficient values was close to 0.996 with the optimal linear correction effect; The RMSE and ΔE values which were corrected by the GOG model were reduced by 37% and 61% respectively. Therefore, the GOG model could be used to achieve the linear correction of CCD response value and improve the accuracy and efficiency of illumination nonuniformity correction in the process of multispectral image data acquisition.