In order to study the moment of each joint during man-machine carrying exoskeleton system walking, taking man-machine carrying exoskeleton system as the research object, the dynamic analysis of weight-bearing walking process was carried out, and the optical capture system was used to collect the test data of man-machine carrying exoskeleton system with a load of 30kg and at different walking speeds. Taking SINESQR function as the basis function and using MATLAB platform to fit the test data, the motion equations of each characteristic Angle are obtained. D ''Alembert''s principle was used to establish the moment equation of each joint, and MATLAB platform was used for analysis and calculation. The variation of the moment of each joint with time was obtained under a load of 30kg and a walking speed of 3km/h, 4.8km/h and 6km/h. It provides a theoretical basis for the subsequent research on the centroid balance of the human-machine exoskeleton.