Objective To study the real releasing of fluorine (F) and its effects on environmen in coalburning-borne fluorosis areas.Methods The coal,clay,briquette,cinder,fresh corn and roasted corn samples from 24 households were collected systematically in Zhaotong of City,Yunnan Province,and the F concentration in all samples was measured using the combustion hydrolysis/fluoride-ion selective electrode method,and the released amount and rate of F in briquette was calculated,and the relation between the released amount of F from briquette and the increase of F in roasted corn was analyzed.Results The F concentration of clay ranged from 266.4 to 2 536.7 mg/kg with a median of 1 087.1 mg/kg;the F concentration of briquette ranged from 115.9 to 635.0 mg/kg with a median of 308.8 mg/kg.The released amount of F in briquette ranged from 63.5 to 432.2 mg/kg with a median of 248.2 mg/kg.The releasing rate of F in briquette ranged from 30.3％ to 91.5％ with a average of 73.8％.The F concentration in fresh corn ranged from 0.43 to 2.00 mg/kg with a median of 1.31 mg/kg;the F concentration in roasted corn ranged from 2.21 to 44.88 mg/kg with a median of 10.49 mg/kg.The increased amount of roasted corn ranged 0.90 to 44.46 mg/kg.There was a significant correlation between the emission amounts of F from briquette and the F concentration in binder clay (r =0.714,P ＜ 0.01),but no correlation between the released amount of F from briquette and the increasing of F in roasted corn (r =-0.155,P ＞ 0.05).Conclusion The clay is an important source of F pollution,and the F increase in roasted corn is not only determined by the released amount of F in briquette,but also by several factors.