Six strains of Eurotium Cristatum fungi marked GF1~GF6 and a strain of Aspergillus niger fungi were isolated from several kinds of dark tea. Preliminary identification of the strains was done by morphology. For the purpose of revealing the influence of fluorine on the six strain of Eurotium Cristatum and one strain of Aspergillus Niger fungi, the growth inhibition rates, mycelial growth rates and mycelial biomass in the treatment of different dosages of fluorine were measured on the plate culture and liquid culture inoculated with single spore. The results showed that six strains of Eurotium Cristatum could grow in 2 000 mg/L fluorine, and Aspergillus niger strain could grow in 1 800 mg/L fluorine under plate culture condition. The growth inhibition rates of Eurotium Cristatum strains ranged from 0.76% to 10.24% while the Aspergillus niger was 35.71% under the dosage of 100 mg/L fluorine. The inhibition rate became higher as the dosage increased. However, the inhibition was more significant under liquid culture condition. The inhibition rate of mycelial biomass of strain GF3 and Aspergillus niger strain under the dosage of 100 mg/L were 34.47%, 80.59% respectively. Ascospore of Eurotium Cristatum and conidia of Aspergillus niger fungi showed more tolerant to fluorine. Also, Eurotium Cristatum strains were more tolerant to fluorine than Aspergillus niger strain both on plate culture and liquid culture.