The concept of a medical parallel manipulator device applicable to chest compressions in the process of cardiopulmonary resuscitation (CPR) is proposed in this paper. According to the requirements of CPR action, a new translational parallel manipulator (TPM) is designed for such applications. And a thorough kinematic analysis and optimization are performed for the designed TPM. The mobility of the manipulator is analyzed using screw theory. The inverse kinematics and forward kinematics problems are solved in details and the singularities are investigated afterwards. Utilizing a numerical search method, the manipulator workspace has been generated with the consideration of factors from medical aspects. The architectural optimization has been carried out based on a mixed performance being a weighted sum of global dexterity index and space utility ratio index, and the simulation results are presented. The research work provides a sound base for the development of a medical manipulator to assist in CPR operation.