A method for image fusion may include obtaining a first image including a plurality of first pixels and a second image including a plurality of second pixels. Each of the plurality of second pixels may correspond to one of the plurality of first pixels. The method may further include classifying the plurality of first pixels into different categories which at least includes a first category and a second category. The method may further include fusing the first image with the second image based on a fusion operation between each of the plurality of first pixels and its corresponding second pixel to generate a fused image. The fusion operation associated with a first pixel belonging to the first category and the fusion operation associated with a first pixel belonging to the second category are performed according to different fusion rules.