The traditional method for solving Jacobian matrix of fully compliant parallel mechanism has the defects of singularity. A microdisplacement method was proposed to solve the Jacobian matrix of the mechanism based on the pseudo rigid body model of a 3-DOF planar fully compliant parallel manipulator. The pseudo rigid body model of the mechanism was established, and the Jacobian matrix of the mechanism was obtained by the micro displacement method and traditional method. The simulation results and the experimental values of the moving platforms displacement of the center point were respectively obtained by HyperMesh software simulation and experimental tests. The theoretical values obtained by the two methods were respectively compared with the simulation values and the experimental values. The results show that compared with the traditional method, the precision of the microdisplacement method is higher and the error is smaller. The validity of the Jacobian matrix is verified. It provides reference for the kinematic analysis of the fully compliant parallel mechanism.