To better regulate and manage flood risk, the supply of ecosystem flood regulation service was evaluated through the SCS-CN model, and the demand of ecosystem flood regulation service was calculated as flood inundation amount through the FloodArea model in Lan County, Shanxi Province. Meanwhile, flood risk zoning was conducted by combining with population distribution. The results are as follows. 1) The supply mount of ecosystem flood regulation service of 5-year, 10-year and 25-year return period flood presented an increasing trend. However, the supply amount for the 10-year return period flood was lower than that for the 5-year by 33.05%, mainly due to the difference in soil moisture. 2) The demand amount of ecosystem flood regulation service of 5-year, 10-year and 25-year return period flood increased gradually. When one 5-year return period flood and one 10-year return period flood occurred consecutively, the flood risk arose principally from the increase in submerged depth. 3) The unbalanced supply-demand area of ecosystem flood regulation service of 10-year return period flood was far larger than those of 5-year and 25-year return period flood, which indicates that the ecosystem flood regulation service supply was not enough to cope with the situation of small and moderate flood occurred in succession. The unbalanced supply-demand area of 5-year and 25-year return period flood was affected principally by elevation and land use, while that of 10-year return period flood was influenced mainly by precipitation. 4) The high priority area of 5-year, 10-year and 25-year return period flood was distributed merely in Dongcun Town, whereas priority area and second-dary priority area were distributed in accordance with the unbalanced supply-demand area of ecosystem flood regulation service. The results can provide theoretical basis for ecosystem service management and flood risk management.