Abstract: The wearable weapon arm is a new kind of exoskeleton of the upper limb of individual soldier, playing an important role in improving the firepower attack efficiency of individual soldier. The man-gun coupling system with weapon arm is a complex man-machine system, and its action mechanism and dynamic response characteristics need further study. In this paper, a general scheme of wearable weapon arm was proposed. Firstly, a prototype of the wearable weapon arm was developed. A 16-channel Delsys surface electromyography test system was used to collect the SEMG signals of the muscles of the left and right arms and trunk of human when the rifle was aimed in the standing position of the shooter, and the muscle fatigue of the shooter with or without the weapon arm was compared and evaluated. A Codamotion three-dimensional motion capture system was used to collect the muzzle response data of the human-gun system under 3 successive firing and single firing condition. Several interaction dynamics simulation models of the human-gun with or without wearing weapon arm were established, evaluating the dynamic stability of the shooter with or without wearing weapon arm. The study results show that the integral EMG value of the shooter's left hand muscles, except for the deltoid muscle, can decrease significantly when standing and aiming with the gun by the weapon arm, especially the bicipital muscle EMG. The displacement of the recoil and vertical direction of the muzzle during firing at standing position with weapon arm can significantly be reduced compared to the shooting state without weapon arm, and the shoulder force can also be significantly reduced, significantly reducing the fatigue of the wearers' hands muscle and improving shooting stability.