This paper collected the observed data from the 11 stations in the typical watersheds of Ganshu Province to establish thestorm rainfall and storm duration relationship model and the maximum flood peak flow and basin characteristics relationship modelfor watersheds, by analyzing the reliability, consistency, representativeness and characteristics of rainstorm and flood based on thetheories and methods such as hydrology and mathematical statistics. The results show that the larger values of the maximum rainstormsin the various periods are mainly distributed in the Jinghe River Basin and the southeast of the Jialingjiang River Basin,and smaller values are mainly distributed in the Weihe River Basin, Taohe River Basin and Beiyu River in the Jialingjiang RiverBasin. The following results were obtained from the relationship curves between the maximum storm rainfall and rainstorm durationat the various representative stations. Firstly, the rainstorm intensity has the turning point at 90min in the Jialingjiang River Basinand at 180min in the other basins. Secondly, the rainstorm increases sharply with the rainstorm duration lengthing when the rainstormintensity is less than the turning point. This trend becomes gentle and steady when the rainstorm intensity is greater than theturning point. The generalized models of rainstorm flood were estabished for the various watersheds by analyzing 330 short durationrainstorm floods which are harmful and difficult to prevent. The short duration floods occur in a short time. The rising time offloods is about 2-5h, and flood peak appear during 5-7h. It is of great significance for local drought relief, flood control and disasterreduction, water resources management, small watershed management and ecological environment protection to study the changerule of hydrological elements in typical small watershed, analyze the characteristics of local short-duration rainstorm and flood, andsimulate its change process.