Purpose: To estimate the prevalence of pterygium and its influence on visual acuity in aged population of Doumen County, south China.Methods: Apopulation-based survey was conducted in Doumen County, the rural area of south China. Twenty-seven sample units were selected by random sampling. The prevalence and severity of pterygium and it-related low visual acuity were analyzed.Results: Of the total 4 762 individuals aged 50 years or over, 4 214 were examined. The prevalence of pterygium was 33.01% in subjects aged 50 years or above. There was a significantly higher prevalence in female (35.70%) than in male (29.70% , P ＝0.025). The prevalence of pterygium in age groups of 50s, 60s, 70s and 80s years old is 33.98%, 36.40%, 30.73% and 25.40%, respectively. Most of the pterygia were located in the nasal side (93.31%) of cea, and only 6. 69% in the temporal side. 0.92% of the eyes had visual acuity less than 0.32, which were directly caused by pterygia.Conclusion: The current survey suggests that the pterygium is one of the most common diseases of extal eye in the population aged 50 years and above. It is still leading to the impairment of visual acuity in the rural area.