Abstract: The average river flow width of ten main river segments in Lhasa River drainage basin were obtained with the help of remote sensing data of Google Earth after gauging the river width of 451 reaches. On this premise, the correlation between river flow width and five topographic factors, inclusive of river’s longitudinal slope, river’s tortuosity, river’s concavity, upstream catchment area and catchment average slope, were plotted with four different functionslinear function, exponential function, logarithmic function, and power function. Results implied that, among the five factors, upstream catchment area is of the largest correlation with river flow width with the coefficient of certainty amounting to 0.81 when fitted by linear function; longitudinal slope of river also has a remarkable impact on river flow width, with the coefficient of certainty reaching 0.76 fitted by power function and exponential function. Researching the correlation between river flow width and topographic structure factors in Lhasa River drainage basin would be of crucial significance for us to understanding the river geomorphology in Qinghai-Tibet Plateau and improving our ability of estimating flow rate and total flow amount in ungauged basins.

Key words: Lhasa River basin, river flow width, topographic structure factors, correlation analysis, Google Earth