To solve the real?time problem of traditional multi?exposure image fusion and ghost elimination in dynamic scenes, a multi?exposure high dynamic range(HDR) image reconstruction algorithm based on gray scale mapping function modeling is proposed. For low dynamic range(LDR) image sequence of arbitrary size, only visual adaptation S?shaped curves with the same the number of gray?scale need to be fitted, rather than the camera resolution pixels. The HDR can be achieved by fusing the best imaging values directly, which can greatly improve the efficiency of the algorithm fusion and achieve real?time requirements for dynamic scene. The ideal state of multi?exposure image can be achieved by the design of the gray level mapping function. The ghost can be eliminated through moving target detection with difference method. Finally a HDR image reflecting the real scene information and unaffected by ghosts can be achieved.