To solve the problem of piston striking cylinder and pumping insufficiency, an optimization method of concrete open-loop pumping displacement control is derived and presented. In order to control piston stroke effectively, the optimization model of concrete open-loop pumping displacement control parameters is built based on considering the system’s open-loop characteristics. Satisfying the physical constraint of preventing piston striking cylinder and maximizing piston’s effective stroke are taking as the evaluation criterion during the modeling process. Using this method, simulation and experimental research has been proceeded in a type of concrete pump. The result shows that concrete pumping piston can not only meet the noninterference physical constraint, but also increase the pumping efficiency significantly under variable loads. The optimization model provides a new method that can be used in engineering practice for solving the design problem of concrete pumping open-loop control system under variable loads.