Objective To estimate the prevalence of cataract and its surgical coverage rate together with the burden related to bilateral cataract-blindness,among adults aged 40 or above in Gongshan county of Yunnan province and to evaluate the current cataract status and the efficacy of local cataract prevention program.Methods Cluster sampling was used.The protocol consisted of personal interview,pilot study,visual acuity checking,measuring the intraocular pressure; slit lamp microscopy and the fundus of the eye examination etc.Cataract was graded clinically using the Lens Opacity Classification System (LOCS) ]Ⅲ.Bilateral cataract-blindness burden,bilateral cataractblindness burden and cataract surgical coverage rate were calculated respectively,using two different criteria.Odds ratios (OR) were compared among different groups regarding age,gender,education,ethnic group and altitude of living area.Results Among the 1236 eligible residents,1116 (90.3％)were enrolled in the present study.The prevalence of cataract was 23.8％ among adults aged 40 or order.When the bilateral best refractive vision ＜3/60 was defined as the blindness criterion,the bilateral cataract-blindness burden showed as 1.3％,and cataract blindness surgical coverage rate was 50.0％.When the bilateral presenting vision ＜ 6/60 was defined as the blindness criterion,the bilateral cataract-blindness burden was 25.0％,and cataract blindness surgical coverage rate was 12.9％.The cataract surgical coverage rates were much lower and the bilateral cataract-blindness burden much higher in women,illiterates,living in high altitude areas and those who were aged 70 or above.Conclusion Cataract blindness was a serious public health problem in aged individuals and illiteracy in the residents of the studied areas.Poor prevention programs on cataract called for urgent action to be taken.