One of the remarkable features of urbanization is the dramatic change in the landscape pattern. A large number of impervious surfaces replaced the natural or semi-natural land cover types, which greatly interfered with the hydrological cycle in the region. The most direct manifestation is the impact on the surface runoff process. As an important mode of urbanization in China, urban agglomerations have a spreading mode of expansion, which is more serious to the regional surface runoff. In this paper, the Long-Term Hydrologic Impact Assessment model (L-THIA) was used to simulate the average annual surface runoff under different land use/cover conditions in Beijing-Tianjin-Hebei urban agglomeration, by using five periods of land use data in 1980, 1990, 2000, 2010, and 2015, the soil data and daily rainfall data from 1950 to 2015 as input. The results show that (1) by calibration, the L-THIA model can accurately simulate the surface runoff of the Beijing-Tianjin-Hebei urban agglomeration, and the simulation error is between ±10%. (2) From 1980 to 2015, the impervious surface area of Beijing-Tianjin-Hebei urban agglomeration increased dramatically, with a net growth value of 12690.14 km². The impervious surface area of megacities such as Beijing and Tianjin increased the most significantly. (3) From 1980 to 2015, the surface runoff in the Beijing-Tianjin-Hebei urban agglomeration showed an obvious increasing trend. The surface runoff in the Beijing-Tianjin-Hebei urban agglomeration increased by 1.784 billion m³ and the relative growth value was 11.83%. The average annual growth rate of surface runoff was larger during 1990-2000 and 2010-2015, 0.36% and 0.46% respectively. The cultivated land and impervious surface contributed more to surface runoff in the study area. The average runoff contribution rates of these two land use types under five land use scenarios were 35.38% and 22.71% respectively. (4) From the perspective of urban scale, the Normalized average annual runoff depth values of different cities vary greatly. Tianjin and Shijiazhuang have strong runoff production capacity, Chengde and Hengshui have weak runoff production capacity, and Beijing's Normalized average annual runoff depth(NAARD) is at the medium level. In addition, there are great differences in the growth patterns of NAARD in different cities. From 1980 to 2015, Tianjin had the largest runoff growth, Chengde had the least growth, and the growth value of NAARD in Beijing was at a moderate level. This study is of great reference significance for revealing the spatio-temporal evolution of hydrological processe in the Beijing-Tianjin-Hebei urban agglomeration and guiding the optimization of land space.