To improve the monitoring efficiency of water noise on the operation status of overflow facilities, it is necessary to clarify the formation mechanism of water noise and its relationship with the operating and structural parameters of overflow facilities.The formation mechanism and influencing factors of water noise of common overflow facilities of river channels and hydropower stations were analyzed and summarized. It is concluded that the characteristics of water noise of common overflow facilities are closely related to their operating conditions and channel structure characteristics. The flow velocity and flow rate are positively correlated with the noise level of water flow. The more complex the flow channel structure is, the more intense the flow turbulence is and the more complex the formation mechanism of water noise will be. The water noise level and frequency of overflow facilities change synchronously with the hydrodynamic characteristics and structural boundary characteristics of the passage, which can be used as the state signal source for the operation of overflow facilities. Monitoring the operation state and safety in real time can ensure the safety of overflow facilities.