The trajectory planning of the manipulator with six degrees of freedom is an important part, which influences kinematics performance of the robot and ensures the manipulator to complete the task quickly and stably. Based on the D-H coordinate system, the kinematics model of the manipulator was established and the forward and inverse kinematics equations were solved. The 4-3-4 polynomial joint interpolation algorithm was employed to plan the path of the six degrees of freedom manipulator. The manipulator was simulated by MATLAB to output the position, velocity and acceleration curves of each joint.Based on the simulation results, the 4-3-4 trajectory planning method was compared with the cubic polynomial trajectory planning. The results show that manipulator can reach the desired position and complete the designated task by the 434 polynomial interpolation trajectory planning method.