Abstract: Abstract：According to sources of fluorine in groundwater, fluorosis in Jilin Province can be divided into four types: 1. Deep-cycle hot water type: the fluorine in groundwater originates from the release of granite magma. Fluorine prevention in drinking water could be carried out by improving crevice-pore water in Neogene sediments and cave-crevice water in basalt. 2. Volcanic activity-enrichment groundwater type: the fluorine in groundwater originates from the release of magma during volcanic activity, and fluorine prevention could be conducted by improving crevice-pore water in Cretaceous sediments; 3. Displacement-enrichment groundwater type: the fluorine in groundwater originates from rock weathering and leaching, with the source from the Da Hinggan Mountains, eastern high plains and Songliao watershed. And it forms high fluorine groundwater when it moves into regional runoff-catchment area and regional catchment area. Fluorine prevention could be performed by improving crevice-pore water of Neogene Taikang Formation and Da’an Formation as well as Cretaceous Mingshui Formation, Sifangtai Formation and Nenjiang Formation. 4. Eluviation-enrichmert type: the fluorine in groundwater originates from the loessial soil and mild clay. Fluorine prevention could be implemented by improving crevice-pore water of Cretaceous Qingshankou Formation.