The assembly of vacuum vessel (VV) is a vital task for the fusion reactor. This paper introduces simulation of a parallel robot built up for the assembly of fusion reactor CFETR (Chinese Fusion Engineering Test Reactor) to carry out welding of adjacent VV sectors using splice plates, and machining in case some sectors need to be replaced for repair. The kinematics and dynamics equations of the robot are obtained, and a non-singular terminal sliding mode controller is designed which overcomes the drawbacks of the conventional linear sliding mode control. The stability of the system is verified using the Lyapunov stability criteria. The proposed method is tested by defining a trajectory for the robot’s end-effector and simulating the multi-body model of the robot.Post-print / Final draf