The invention discloses a foreground partition method for overcoming sudden lighting change. The foreground partition method includes initializing a processed video frame grey map by a mixed Gaussianbackground modeling model; performing mixed Gaussian background modeling according to the quantity of sudden light intensity change to acquire an updated background model; extracting a foreground target according to link domain marking, feature extraction and behavior judgment results. The foreground partition method has the advantages that the quantity of the sudden light intensity change is introduced into the model to process images on the premise of a conventional mixed Gaussian background modeling method, the background model is updated in real time, the problem that target partition is sensitive to sudden change of lighting and environments is solved, the problem that a target stable for a long time is updated into a background and disappears in a conventional mixed Gaussian background model is also solved, and accuracy of foreground partition is further improved. The foreground partition method can be applied to the image processing field.