Channel width is an important hydrological feature, which is of great significance to the hydrological calculation of the rivers in Tibet Plateau. The channel widths of 1000 rivers in Lhasa River Basin were measured using Google Earth images, and the corresponding catchment area, local slope, origin moment of slope and channel curvature of each channel section was calculated accordingly. The correlation between channel widths and these topographic factors were evaluated based on the data of 800 channel sections. Then channel width models based on catchment area, origin moment of slope and four channel width factors were constructed subsequently. The other 200 channel width data were used to verify the precision of the models. The results show that the channel width factor model based on catchment area and origin moment of slope with the catchment area less than 2 100 km2 in the upstream section has the best performance and the model based on catchment area with the catchment area more than 2 100 km2 in the downstream has the best performance. Thus, the catchment area threshold of 2100 km2 should be applied in the prediction of the river width in Lhasa River Basin, with the application of channel width factor model to the upstream channels, and catchment area model to the downstream channels. The average deviation of the prediction result is less than 20%.