Abstract: The existing flood resource benefit identification methods of the tabulation method, the analytical method and the illustration method are thought as the only benefit from the angle of flood resource. A new coupling benefit identification method of function and requirement is proposed and the related mathematics model is established. Focusing on water use system, through function matching requirement, supply coupling demand and initiative fitting passivity, the concrete benefit is identified. This paper takes Baicheng City as an example to study and analyze the comprehensive benefit of flood resources.