Abstract: Counter balance valves are critical components in the lifting machinery equilibrium circuit for preventing overrunning loads. However, under high-pressure and large-flow conditions, they are prone to significant noise generation, adversely affecting system stability. To mitigate this noise, this study employs full-scale flow field numerical simulations to investigate the internal flow characteristics of a pilot-operated counter balance valve. The results indicate that turbulent kinetic energy and noise sources within the valve cavity are predominantly concentrated in the valve orifice and damping tail regions. The primary causes of this turbulent noise are identified as high-speed jets, fluid impact on walls, and shear vortices. Based on these findings, an improved structural design featuring a damping tail with staggered grooves is proposed. Simulation verification demonstrates that this modified structure effectively reduces noise while preserving the damping tail's primary function of balancing hydrodynamic forces.