Taking Dahuofang reservoir in Liaoning province as a case study,the paper first employ cause-analysis methods to research the flood season separation relevant problems of reservoirs, and then used rainfall amount and inflow as indicators to determine the separation and cutting-off point of flood season. Finally it analyzed the rationality and feasibility of the proposed strategies from the perspective of water resources utilization, and proposed the research direction of improving the utilization efficiency of flood water resources in Dahuofang reservoir. The strategies and methods of flood season separation proposed in this study should consider the combination of multi-separation indicators and multi-separation methods as much as possible and must be reasonable and reliable. The result can also provide useful guideline of solving the flood season separation problems for other reservoirs.