Abstract:The division of protection areas for groundwater sources will improve the security level of groundwater. Due to heterogeneity and anisotropy of aquifers, it is difficult to divide water source protection areas reasonably and accurately. Taking Caolou water source in Ji'nan city as the research object,on the basis of fully collecting and analyzing hydrogeology, water quality, topography and other data of the water source,by using combination method, water source protection areas have been divided. Correction of the scope of protected areas has been carried out based on topographical and geological conditions in order to protect water sources from pollution. The water source protection area divided by the combination method has strengthened the protection of the upstream recharge area, especially main groundwater runoff zones, and the division result is more in line with reality. By using this method, the protection of main recharge area of the water source can be improved, sustainable development and utilization of groundwater can be ensured, and a scientific basis and some references can be provided for the protection of water source.