Abstract: The boundary area of the East-Asian summer monsoon in China is an important farming-pastoral ecotone that is ecologically fragile and sensitive to climate changes. The complex geographical, ecological and climatic environment creates an unique spatial pattern and temporal evolution of land surface energy fluxes, which are critical for the understanding of regional weather and climate changes. However, knowledge of characteristics of the land surface process in this region is still very limited due to the lack of sufficient land surface observations. In this study, 34 a of land surface model outputs were analyzed. It is found that the latent and sensible heat fluxes exhibit a significant transition feature in the summer monsoon boundary area with a greater gradient within the boundary area than that outside the area. Surface energy balance displays obvious regional features that are characterized by a "ladder-type" change in the net surface energy flux at both latitudinal and meridional directions. Relatively large radiation and sensible heat fluxes and small latent heat flux are found in the central boundary area. Regional averages of sensible and latent heat fluxes show no regular decreasing or increasing trend with amplitude variations within ±20%. Before 1997, the summer monsoon was relatively active and the latent heat flux in this region was higher than its climatological value while the sensible heat flux was lower than its climatological value; after 1997, the opposite phenomenon was observed. In addition, the sensible and latent heat fluxes are very sensitive to the hydrological component of the climate system, and there exists a significant linear relationship among them.