The River Chief Policy (RCP) is an innovative water resource management system in China aimed at managing water pollution and improving water quality. Though the RCP has been piloted in some river basins of China, few scholars have studied the effects of the policy. We built a differential game model under random interference factors to compare the water pollution in Chaohu Lake under the RCP and without the RCP, and we explored the conditions to ensure the effectiveness of the RCP. The results showed that: (1) The average effect of water pollution control under the RCP was greater than under non-RCP; (2) the higher the rewarding excellence and punishing inferiority coefficient ( θ ) was, the better the water pollution control effect under the RCP; (3) the greater the random interference coefficient ( σ ) and rewarding excellence and punishing inferiority coefficient ( θ ) were, the bigger the fluctuation of the water pollution control effect was; (4) when using the stochastic differential game, when σ ≤ 0.0403 , θ ≥ 0.0063 , or σ > 0.0403 , θ ≥ 0.268 , the RCP must be effective for water pollution control. Therefore, we can theoretically adjust the rewarding excellence and punishing inferiority coefficient ( θ ) and the random interference coefficient ( σ ) to ensure the effective implementation of the RCP and achieve the purpose of water pollution control.