At high altitudes, glacial melt water is an important source of replenishment for rivers, and the Lhasa River, as the largest tributary of the Brahmaputra River in the southern part of the Qinghai-Tibet Plateau, is an important part of its runoff. This paper simulates the runoff process of the Lhasa River Basin from 1990 to 2010 based on the VIC_glacier model constructed by the VIC model and the day model. The results showed that: 1) the correlation coefficient of the simulation effect was close to 0.8, the relative error of the VIC_glacier model considering glacial melting was reduced by about 20% compared with the original VIC model, and the Nash coefficient was increased by about 0.1; 2) the proportion of glacial melt water from upstream to downstream Punduo, Tangga and Lhasa stations was 21.4%, 17.7% and 14.5%, respectively, and the contribution of glacial meltwater gradually decreased. 3) From 1990 to 2010, the overall trend of glacial melt water increased, increasing by 180 million cubic meters of water per year; 4) the proportion of glacial melt water runoff in spring was the highest, and the contribution rate of spring melt water rose slowly with the temperature, and the inter-annual variation characteristics were consistent with the temperature change. This study provides a scientific basis for the management and application of water resources in the cold plateau areas such as the Lhasa River Basin.