Abstract: By using ion-selective electrode method, the fluorine content of fish bones was determined for 1 600 samples of 12 fish species from 186 locations in 12 areas.Some sam ples from Huanghe River and Qinghai Lake were also analysed.Data on the fluorine content of fish bones exhibited a lognormal distribution.Statistical analyses were made on the differences in fluorine content among different species and among different water systems.The ef fects of biotic and abiotic factors were discussed.