Abstract: A four-quadrant radial piston hydraulic device includes a housing, plunger assemblies, an eccentric spindle rotatably disposed on the housing, pilot-operated check valves one-to-one corresponding to the plunger assemblies, two-way cartridge valves one-to-one corresponding to the plunger assemblies, a distribution shaft and a confluence plate. A reversing slide valve is disposed on the confluence plate. A working method of a four-quadrant radial piston hydraulic device is also provided. When the radial piston hydraulic device is used as a hydraulic motor and a hydraulic pump, it is capable of realizing two-way rotation, which solves a limitation of valve flow distribution in motor application.