In order to reveal the influence of climate change and human activity on runoff in the Taizihe basin, based on conventional observation data including temperature and precipitation at five meteorological stations and runoff at a hydrological station of Liaoning Province during 1961-2018, the trend and mutation characteristics of runoff, areal precipitation and potential evapotranspiration were analyzed statistically by using linear regression analysis and cumulative anomaly methods, etc. And on this basis, the contributions of climate change and human activity to runoff change were estimated quantitatively by using slope change ratio of cumulative quantity (SCRCQ). The results show that the runoff and areal precipitation, potential evapotranspiration decreased slightly in the Taizihe basin during 1961-2018 as a whole, and the significant mutation of runoff and areal precipitation occurred in 1975, 1984, 1996 and 2009, while that of areal potential evapotranspiration occurred in 1983. The correlations of runoff with areal precipitation, potential evapotranspiration were extremely significant, and the runoff increased with increase of precipitation and decrease of potential evapotranspiration. The study period was divided into five stages according to the abrupt point of runoff. Compared with the base period (1961-1975), the contribution rates of climate change to runoff decrease were 23.24%, -0.08%, 18.57% and 28.45% during 1976-1984, 1985-1996, 1997-2009 and 2010-2018,  respectively, while for human activities they were 76.76%, 100.08%, 81.43% and 71.55%, respectively, which indicated that the human activities played an dominant role in decreasing of runoff in the Taizihe basin.