Groundwater contains high fluoride in north areas of Gaomi are rather wide.It is typical high fluoride areas.Local residents have different degrees of illness because of long-term drinking groundwater.Different regions with different fluoride contents in groundwater are classified,quantity of fluoride translated into water in different strata of Mesozoic and Cenozoic are studied,and high fluoride-forning mechanism and prevention countermeasures are put forward in this paper.