Abstract: The surface reflectance is an important parameter controlling surface energy balance. However, the heterogeneity of the distribution of urban buildings makes it difficult to collect in-situ measurements of surface reflectance. Therefore, there are few studies published on the measurements of urban reflectance (albedo) although there are a large amount researches on natural surfaces, such as crop, forest and desert. The complex urban canopy makes it difficult to simulate urban surface reflectance because of the difficulty in describing the urban configuration. Therefore, the urban areas are not well presented in the current land, atmospheric and climate models. This issue is addressed in this paper. In this paper, a three-dimensional model is proposed, which is of high accuracy and high speed by combining the advantages of Monte-Carlo method and geometrical optical method. The model can simulate the surface reflectance over different urban configuration by incorporating “city map”. The MODIS (MODerate Resolution Imaging Spectroradiometer) bands 1－7 reflectance measurements during 2002－2004 are selected to validate the model. The MODIS TOA (top-of-atmosphere) reflectances are corrected for the atmospheric effect using the data of aerosol and water vapor collected by Beijing AERONET site with 6S (Second Simulation of Satellite Signal in the Solar Spectrum) atmospheric radiation transfer model. The validation results show that the model simulations of the surface reflectances are closely related to the MODIS measurements, with the correlation coefficients varying from 0.80 to 0.93, which means that the model proposed here can simulate the influence of solar and view angle on surface reflectance over urban areas. Finally, the influences of the urban configuration on the surface reflectance are discussed.