Aim to improve the slope type of automated pharmacy prescription medicine efficiency of the manipulator, to guarantee the stability of the prescription system, five degrees of freedom （5-DoF） manipulator on drugs is researched. The mechanism composition and working principle of the manipulator were made, and based on programmable logic controller (PLC) and its hardware and software of the control system made detailed introduction. Rotation symmetric dual-drug agencies were highlighted, through the teeth meshing to achieve the reservoir tank inverted so that the drug reservoir by gravity principle slidded into the medicine cabinet. Through timely monitoring system by monitoring the drug situation robotic movements, using RS485 bus communication, data were transmitted to complete the operation of the robot drug control according to the operational requirements. The result shows that: under electromechanical control systems and software control systems complement each other, the drug manipulator system enables stable and high efficient work.