The changing nature of the earth's climate and rapid urbanization lead to the change of rainfall characteristics in urban areas, and the stability of rainfall series is destroyed, it is a difficult challenge to consider this change in urban drainage simulation. A variety of methods are used to test the stationarity of annual maximum rainfall intensity series of Zhengzhou meteorological station from 1981 to 2010, and the intensity-duration-frequency (IDF) curves of changing environment are fitted by GAMLSS model and further generalized into short duration rainstorm intensity formula. The 3-hour design rainstorm in different scenarios was used as the input of Mike Flood model to simulate the operation of the campus drainage system of Zhengzhou University. Results indicated that: The rainfall series is non-stationary and has an increasing trend. Although the parameters of the short duration rainstorm intensity formula have no fixed change rules, there are traces to follow in the design rainstorm. According to Mike Flood model, the non-stationary scenario provides a series of dangerous signals such as more flood volume, larger inundation area, higher flood depth and slower recession process. The flood volume of the non-stationary scenario is 23.5% more than that of the stationary scenario, and the inundated area is 18.5% more when the return period is 5 years. In the future, the difference is 34.0% and 24.6% respectively, and it can reach more than 50% when the return period is once in two years. We will discuss the non-stationarity and challenges brought about by changing environments.