This paper analysed the motility of a new triangular-platformed 3-PRC parallel manipulator with screw theory, and the movable platform's motion path of the 3-PRC parallel mechanism was studied by using the theory of inverse kinematics of the parallel mechanism. The computation formula of inverse kinematics was deduced according to the homogeneous transformation, then the movement rules exerted on the actuator was achieved when one point of movable platform is moving on the desired trajectory. The virtual prototype of this mechanism was created in UG software and at last the planning trajectory was verified through simulation in ADAMS.