The southwestern Song -Nen plain is one part of Northeast plain of China. In this area, both F contens and the incidence of local F diseases are very high.The paper is based on the study of F content level in some local environmental factors including soil, food, vegetable and drinking water. It points out that F content in shallowlayer underwater used as the drinking water before is high. It is the main factor of causing high incidence of local F diseases. It also suggests that drinking deep-layer underwat...