High pressure pump is one of the key components in Sea Water Reverse Osmosis (SWRO) desalination project. This paper introduced the development of an axial piston pump prototype which used as a high-pressure pump in SWRO desalination system. After the structure and technique data of the pump were illustrated, the main manufacturing processes of the prototype were introduced. The performance test of the prototype was carried out on an integrated water hydraulics test rig. After this, the prototype was used as a high-pressure pump on a SWRO experimental system. The test and application results prove that the pump is more efficient and quiet than other types, and is suitable for being used as high pressure pump in small and medium scale SWRO desalination project.