In the field of forging machinery and construction machinery, the hydraulic transmission has become the preferred transmission mode for its high efficiency. The hydraulic pump is the core component of the transmission system as the power component. It is also the main research focus in the field of hydraulic transmission in recent years. According to the axis direction of the piston and the drive shaft, the piston pump can be grouped into radial piston pump and axial piston pump. There are two shafts in the conventional radial piston pumps, which are distribution shaft and drive shaft to complete distribution the pump and transmission work, and the friction between the shoes and the stator is high for its high load and relative sliding speed. In order to reduce the impact of these drawbacks on pump performance, a valve plate is designed to distribute the oil to avoid the stress of the conventional distribution shaft in this paper. The working principle of the radial piston pump is discussed. An electro-hydraulic proportional servo control system was adopted to control the displacement of the pump. The design and manufacturing of the radial piston pump were completed. A test platform is carried out to test the performance and the variable displacement control system of the radial piston pump with a good test result. The radial piston pump has a certain novelty in structure and has practical value.