In order to analyze the variation law of rainfall and runoff control rate in different return periods, this research through using two-dimensional urban flooding model based on GPU acceleration technology and coupled with a pipe network system developed by author. This work adopted to quantitatively analyze the runoff control rate of the district by simulating the runoff control effect of the district under the typical design rainfall process. The results indicate that the simulated flow process is in good agreement with the measured value through comparison and verification with the measured data. With the increase of rainfall return period, runoff control rate gradually decreases. Under the condition of rainfall once a year, the runoff control rate is 82.5%, and under the condition of rainfall once a hundred years, the runoff control rate is reduced to 29.5%. With the increase of return period, the difference of runoff control rate gradually decreases and the decreasing trend of runoff control rate gradually flattened.