The invention discloses a linear filter and non-linear filter combined heterogeneity correction method. When a linear correction image undergoes spatial smoothing filtering to obtain an estimated image of a real scene, if the heterogeneity level is high, a mean filter with a template of 11*11 is used, or else a non-linear smoothing filter with a template of 5*5 is used, the self-adaption iteration step length of correction parameters is calculated while the filter at the edge is retained, detection and replacement of abnormal pixels (damaged elements and impulse noises) are performed, a filtering output image serves as the estimated image of the real scene, change detection is achieved by utilizing a change reference image, and iteration update is performed on a heterogeneity correction coefficient only when the difference between the correction image and the change reference image is larger than a change threshold. The linear filter and non-linear filter combined heterogeneity correction method has the advantages of large smoothing effect and quick convergence speed of a linear smoothing filter, has the edge-preservation characteristics of the non-linear smoothing filter, and is low in computing complexity and suitable for hardware circuit achievement.