In order to explore the impact of changing environmental conditions on the safety of drinking water sources, based on the connotation of the safety of water sources, a safety evaluation index system of lake drinking water sources in Jiangsu Province with 12 indicators including water resources, eutrophication index, benthic diversity, and human activity intensity has been constructed from 5 aspects of water quality, water quantity, ecology, environmental risks and construction standards. A comprehensive weight calculation model combining subjective and objective is used to determine the weight of each indicator, and a scoring method is used to comprehensively evaluate the safety status of 13 typical lake drinking water sources in Jiangsu Province. The results show that the overall safety status of typical lake drinking water sources in Jiangsu Province is relatively good, and the key indicators affecting the comprehensive safety of water sources are water quality indicators and ecological indicators.