In this paper, we applied a continuous fractionation method to analyze the spatial distribution, occurrence characteristics and release of fluorine in the interstitial water, surface sediments and core sediments of DaiHai Lake, with aiming to reveal the migration and transformation of fluorine in the water-sediment of DaiHai. Investigation results showed that the average of the fluoride ion concentration in the interstitial water was (4.82±0.06)mg/L, which largely exceeded the threshold in National surface water standard criterion Ⅴ(1.5mg/L). Moreover, the relative concentration of fluoride ion between the interstitial water and the overlying water(4.77mg/L) remained stable. The average of the total fluoride in the surface sediments was (934.13±36.79) mg/kg, including (34.39±1.69)mg/kg water-solution fluoride, (7.11±0.93)mg/kg exchangeable fluoride, (3.07±0.50)mg/kg Fe/Mn bound, (11.97±0.79)mg/kg Organic bound and (934.13±36.79)mg/kg residual fluoride. In the core sediments, the fluoride ion concentrations of water-solution, exchangeable, Organic bound reduced with sediment depth increasing, and kept stable under 40cm; however, the fluorine of Fe/Mn bound was low in the surface and became stable under 25cm. Depending on the multiple regression analysis, both the amount of the water-solution fluorine and exchangeable fluorine of the sediment had much positively correlated with the fluorine in the interstitial water, and the fluorine had a strong migration ability. The stability risk assessment indicated that the range of SAC in the surface sediments was between 55.53%~69.52%, with the average being 60.63%, but in a largely unstable state. In addition, the SAC would decrease from the surface down 20cm, which indirectly reflected that the concentration of extractable fluoride had been obvious in recent years, with strong releases risk.