Snow grain size is a key parameter to control the snow surface energy balance and represent the state of snow.The quantitative retrieval of surface snow grain size using remote sensing techniques is significant to many researches on the estimation of snow water equivalent,basin water resources management and local climate change.In this study i)a snow grain size retrieval model was developed based on Asymptotic Radiative Transfer(ART)model for the mountainous areas in Manasi River Basin,Xinjiang Province;ii)the snow grain size in both winter snow accumulating and spring snow melting periods was obtained using the multi-spectral observations from the environment and disaster monitoring and forecasting satellite(HJ-1);iii)the retrieval results were validated using the ground sampling data;and iv)the grain size distribution in altitude was analyzed.The results indicate that the developed model could accurately describe the relationship between snow grain size and remote sensing data,the snow grain shape has a considerable impact on the retrieval accuracy that retrieved snow grain size has a good agreement with ground measurements only when proper snow grain shape was considered in the model,and the distribution of snow grain size is dependent significantly on altitude.