Abstract: Aiming at the problem of rainwater runoff pollution around Erhai Lake, surface runoff water quality monitoring in typical functional areas such as residential commercial areas, industrial areas, rural residential areas, and farmland areas in the Erhai Lake Basin were carried out during the rainy season. The satellite remote sensing images were used to divide the area of each functional area, and the storm water runoff generation was estimated combined with the underlying surface of the region. The runoff pollution load of regional rainy season was preliminarily calculated as 2263.45 t/a of COD_Cr, 329.42 t/a of TN and 31.21 t/a of TP, and corresponding prevention and control suggestions were put forward according to the investigation results.