In order to design the high-speed planar 3-DOF parallel mechanism, the direct kinematics was studied comprehensively. Velocity and acceleration characteristics of mechanism were gained. With the driving parts movement, all the forward position configurations were obtained. According to the continuity conditions of movement, the optimal trajectory of moving platform was planned. The velocity and acceleration characteristics of mechanism were implied. The mechanism was divided into stroke unit and plane triangle unit. The finite element model of the mechanism was established. By combining kinematics, the moving platform was moving along the planning track, the modal frequency and main vibration mode of the mechanism with the change of mechanism position and posture were analyzed. Variation law of elastic displacement error and the dynamic stress of mechanism was obtained by researching the dynamic response of mechanism in drive force and inertial force excitation. Therefore, the kinematics and the dynamic performance of mechanism were assessed comprehensively. 