In order to avoid the patients in the ambulance suffering from the secondary injury caused by the vibration of the car body,a new type of 2-UPS-2-(RP-RR) U symmetrical parallel vibration isolation device was proposed based on the screw theory and full Jacobian singularity analysis.The mechanism has two rotational degrees of freedom and two mobile degrees of freedom (2R2T).Based on the screw theory and the relationship between the rigid body axis and the constraint screw,two continuous axes of the moving platform were determined.One of the axes was a fixed axis,which was independent of the configuration of the mechanism and passed through the origin of the static coordinate system and along the Y axis;the other axis was arbitrary,which was related to the configuration of the mechanism.The motion continuity of the mechanism was verified by the two U pairs of center points of the moving platform.The closed-loop vector method was used to establish the inverse kinematics model of the mechanism,combined with the boundary search method,the workspace of the mechanism was simulated in MATLAB,the correctness of the motion model was verified.