Precipitation over the lake surface is one of the essential factors affecting the water quantity and quality of the lake. This article uses precipitation observation data from 11 meteorological stations around Erhai Lake to analyze the precipitation characteristics around the Erhai Lake and based on the natural neighbour interpolation method, the precipitation over Erhai Lake is interpolated by the 0.01° resolution grid. The results show that the distribution of precipitation on the Erhai Lake has a seasonal feature. The precipitation is largest in summer, the second in autumn, and the smallest in winter. There is also a significantly uneven distribution in space. The highvalue centre exists in the central part of the Erhai Lake, nearby the west bank, and the lowvalue centre exists in the lake area near Haidong Station in the summer and autumn seasons. The spatial and temporal differences in precipitation on the lake surface are significant. This study has a specific reference value for the regional sensitivity study of the impact of precipitation on Erhai water quality and quantity. It offers the technical support for the precipitation prediction on water surface and the research and management of the water environment for the lake.