[Objective] The variation characteristics of non-uniformity for the distribution of annual runoff of Chishui River and its response to precipitation was analyzed in order to provide a basis for decision-making regarding the development and utilization of water resources and flood control in the upper and middle reaches of the Chishui River basin.[Methods] We constructed a database for the SWAT model to simulate watershed runoff. The model was calibrated and validated with measured monthly runoff data. Model output data were combined with precipitation/runoff concentration degree (PCD/RCD) and concentration period (PCP/RCP), and the characteristics of annual runoff distribution and its response to precipitation were determined.[Results] The coefficient of determination (R²) and Nash-Sutcliffe efficiency coefficient (Ens) values for two hydrological stations were greater than 0.83 for the calibration period, and greater than 0.69 for the validation period, which meet the accuracy requirements. The annual distributions of precipitation and runoff was significantly uneven, and the change trends for the two were relatively consistent, with precipitation and runoff mainly concentrated in June to August. The temporal and spatial distributions of RCD were significantly affected by PCD. Due to infiltration and evapotranspiration, watershed RCD was usually greater than PCD. But when PCD<0.3, RCD was no longer dominated by PCD. Due to the lag in the response of watershed runoff to precipitation changes, RCP was often greater than PCP, and a small, short-term increase in precipitation had a significant impact on PCP, but a limited effect on RCP.[Conclusion] Precipitation was the leading factor causing changes in RCD and RCP in Chishui River watershed. Changes in the runoff coefficient in different periods were the main reason for the different response characteristics of RCD/RCP compared with PCD/PCP.