An image synthesis method for a mobile terminal and the mobile terminal are provided. The method includes: performing a phase focusing on an object to be photographed based on a preset pixel of a photosensitive element in the mobile terminal when a user photographs the object to be photographed with the mobile terminal; controlling the photosensitive element to generate a displacement at an initial location to replace the preset pixel by an original pixel, and obtaining a replaced pixel; collecting first photosensitive data of the object to be photographed based on the replaced pixel, and controlling the photosensitive element to return to the initial location; photographing the object to be photographed, and enabling the photosensitive element to collect second photosensitive data of the object to be photographed at the initial location; and synthesizing an image of the object to be photographed according to the first and second photosensitive data.