The invention discloses an area energy photon counting image fusion algorithm based on an adaptive threshold value, and belongs to the technical field of image fusion. The method is characterized by comprising the following steps of step 1001, carrying out redundant wavelet transformation; step 1002, calculating regional energy, neighborhood mean square error, matching degree and self-adaptive threshold value; step 1003, calculating a weighting coefficient and an enhancement factor; step 1004, calculating a matching degree; step 1005, judging a matching degree and a self-adaptive threshold value; step 1006, when the matching degree is smaller than a self-adaptive threshold value, selecting an enhancement value of a pixel point of an area with high energy as a corresponding pixel point value in the fusion image; step 1007, if the matching degree is greater than or equal to a self-adaptive threshold value, adopting a weighted area energy method; and step 1008, obtaining a photon countingfusion image. Through the algorithm, the problems of unclear contour, serious noise, photon counting image information redundancy under extremely weak illumination, unclear details and the like of afusion image obtained through a regional energy fusion method are solved.