For the dynamic problem of multi joint industrial robots，the expression form of robot Jacobian matrix and the robot dynamic equation based on Lagrange method are provided. A 3D assembly model of a certain type of industrial robot was established using Solid Works modeling software，and the assembly model was imported into ADAMS software for dynamic simulation analysis. The angle，angular velocity，and angular acceleration variation curves of each joint when the robot end-effector moves under a given harsh working condition are obtained. The motion characteristics of each joint are consistent with practical applications. The variation curves of the forces and torques acting on each joint during motion are provided，and the simulation results are consistent with the actual force conditions of the robot joints. The research results of this paper provide atheoretical basis for the selection of driving motors for various joints of robots and the verification of joint strength.