The working performance of a hydraulic system depends on the control valves, and the working performance of the control valves depends on their mechanical properties. Compared with the oil-hydraulic control valves, the water-hydraulic control valves are featured by strict sealing requirements, poor lubricity, and more complicated friction properties . In order to precisely control the valves, the fluid force and friction acting on the valve core are investigated through the methods of finite element analysis and experimental research. The results show that the realizable k-ε turbulence model with an appropriate wall roughness height could accurately reflect the state of fluid force. The fluid force increases as the valve opening and the pressure difference increase. Moreover, the friction is affected by the motion state of the valve core, and the reason is investigated. In addition, the phenomenon of mechanical properties variation is discussed, and an assumption is presented to explain the causation. This research can help understand some mechanical properties of water hydraulic valves and establish a more accurate mechanical model. Furthermore, the study also has guiding significance for controlling water hydraulic valves.