In this study, Luanhe basin was chose as the study area, and sensitivity analysis and double mass curve were used to analyze the effects of climate change and human activities on runoff. The results showed that the runoff in Luanhe basin decreased obviously, and the runoff in the change period (1980—2000) decreased 52.59 mm (50.43%) compared with the reference period (1956—1979); the sensitivity coefficients of runoff to precipitation and potential evapotranspiration were 0.336 1 and -0.123 5, respectively; in this change, the impact of climate change was 22.23 mm, while the impact of human activities was 32.07 mm and accounted for 57.26%, which was far greater than the climate change (39.69%).The human activities were the main impact factors causing the decrease of runoff in the Luanhe River basin.