flood disaster is one of the most common natural disasters. Flood simulation and prediction is an important measure for flood control and disaster reduction. Taking Liulin watershed in Xingtai City, Hebei Province as the research area, this paper processes DEM data with 30m, 90m and 1km accuracy through HEC geohms module, constructs the corresponding HEC-HMS model, simulates 19 floods selected in Liulin watershed, compares and analyzes the impact of different terrain accuracy on flood simulation, so as to explore the applicability of different resolution models in Liulin watershed flood simulation. According to the research results, the qualified rates of peak flood volume of 30m, 90m and 1km precision models are 68.4%, 42.1% and 26.3% respectively; The qualified rates of runoff were 78.9%, 68.4% and 68.4% respectively; The mean value of Nash efficiency coefficient is 0.59, 0.57 and 0.46. The 30m precision model is more suitable for flood simulation in Liulin basin.