Climate change and human activities were regarded as the two main factors for runoff change.Using observed stream discharge, there was a statistically significant decreasing trend for annual and monthly runoff detected by Mann-Kendall's test, in the upper reaches of Luanhe River basin (URLRB), 1954-2000.With the break point analysis, the whole time series were divided into two periods: "natural period (1954-1970) and "impact period" (1971-2000)."Natural runoff" from 1954 to 2000, was reconstructed by variable infiltration capacity (VIC) model, in which the model parameters were calibrated in "natural period" representing the natural land cover conditions without the impact of human activities.By comparing the difference between observed stream flow and "natural stream flow", the contribution of climate change and human activities was quantitatively separated.The results indicated that climate change and human activities accounted for 49# and 51#, respectively, of the annual runoff decrease in URLRB.That meant the contribution of climate change on runoff was equal to it caused by human activities.Monthly, climate change decreased the stream flow in every month; otherwise, human activities increased the stream flow in four winter months: December to March, and reduced the stream flow in other eight months.The results could be a reference for water resources projection and management in URLRB and others catchments in northern China.