Objective To explore the influential facts of betel quid chewing for patients with oral submucous fibrosis (OSF) in Haikou,Hainan Province.Methods One hundred and twenty three patients in the Haikou City People's hospital were investigated regarding their clinical information,including age,sex,origins,kinds and time of betel nut chewing,obvious clinical features,cognition for its harmfulness and so on.Results (1)The mean age was 36.5 years old,the most common patients were the group between the ages of 30 and 50 among 123 patients,male preferred to chewing betel nut,the female fond of betel nut were mostly Li minority women.(2)People chewing the dry betel nut had the higher incidence than the ones who prefer the fresh in five years.The both were significant difference (x2 =18.79,P ＜0.01),however,the incidence difference between the patients at the same time and the ones chewing kinds of betel nut was not significant (P ＞ 0.05).(3)The early clinical features of some OSF patients included stimulating pain,mucosal blanching,gradual inability to open the mouth and fibrous bands.(4)Although 61 patients (49.59％) knew about the harmfulness of betel nut chewing for their oral health,they could not change their lifestyle.Conclusions Male prefers to chewing betel nut,the female fond of betel nut are mostly Li minority women in Haikou area,the parts of patients could not overcome the habit ofchewing betel nut; people chewing the dry betel nut has the higher incidence than the ones who prefer the fresh's at early period,and of the two the former prone to disease than the latter.