Abstract: The law is the primary and the most efficient way of water source protection, which directly affects the effectiveness of water source protection work. Based on analysis of the situation of legal guarantee capability to water source protection for the water sources area ,including 8 cities of 3 provinces, of the Middle Route Project of N-S Water Diversion and the existing problems, some suggestions are put forward: studying the present-day laws and regulations, speeding up revision of Regulations on water supply and management of South to North Water Transfer Project, making and issuing Drinking Water Source Protection Zoning Scheme for Danjiangkou Reservoir Area and Upstream and Regulation of the Middle Route Project of South to North Water Diversion,constructing integrated monitoring network, strengthening united law forcing.