The main objective of this study is how to quickly establish the virtual prototyping model of robot arm system and effectively solve trajectory tracking control for a given signal. Taking the 2-DOF robot arm as an example, a co-simulation control method is introduced to research multi-body dynamics. Using Newton-Euler and Lagrange method, respectively establish the dynamics model of robot arm and verify the correctness of equations. Firstly, the physical model of robot arm was built by PROE and ADAMS. Furthermore, a control model was created in MATLAB/SIMULINK. And then, the co-simulation model was established based on ADAMS/Control and MATLAB/SIMULINK. The simulation results indicate that the robot arm system has preferable response characteristics and nicer locus-tracking ability. The co-simulation method is intuitive and effective. It is no need to create dynamics equation of complicated physical system and has the important practical significance to study manipulation and control for robot arm.