Abstract: In order to explore rainwater resources potential and improve its utilization efficiency in the urban area of Kunming, a modified SCS model was applied to simulate rainwater resources potential of the year 1986, 1995, 2000, and 2014 based on the daily precipitation data obtained from five meteorological stations in Kunming, and their spatiotemporal variation characteristics were analyzed. The results show that:① the modified model applied to Kunming plain region has the average relative error less than 15%; ②potential rainwater resources were 0.3550 billion, 0.2668billion, 0.1800billion, 0.2519 billion cubic meters for the year 1986,1995,2000,2007, and 2014, and the possible rainwater collection and utilization regions are mostly in the construction land and traffic land, with average annual available rainwater resources reaching up to 0.1025 billion cubic meters, accounting for 42.56% of the total amount; ③ rainwater resources are abundant during summer, reaching about 0.1863 billion cubic meters in total, and average rainwater resources for June, July, and August are 0.5949,0.5383,0.7299 billion cubic meters respectively;④ The rainwater resources potential shows an upward trend from 1986 to 2014, its high-value area expands significantly to the eastern and southern area of Kunming, and the potential of available rainwater resources increases year by year.