A trajectory planning method of combing the basis functions superposition and particle swarm optimization is proposed to suppress the vibration. Firstly, the relationship between the state variables of each joint and the modal coordinates of the flexible body is derived. Then, sinusoidal-trapezoidal functions are used as basis functions to construct joint angular velocities. The coefficients and amplitudes of the basis functions are considered as the parameters of the joint rate functions to be determined. Then, the vibration minimized trajectory planning problem is transformed into an optimization problem of the unknown parameters. And the PSO algorithm is utilized to search the optimal parameters. Finally, a two-link rigidflexible hybrid manipulator is taken as the example and simulation study is performed. Simulation results show that the proposed method largely reduces the residual vibration of the end-effector.