Abstract: Objective: To investigate the detection rate of duodenal bulbar ulcer for the relation between duodenal bulbar ulcer and sex,age,season. Methods: A retrospective analysis of 382 cases of duodenal bulbar ulcer diagnosed by gastroscopy in 2 818 out-and in-patients was made.The cases were divided into different groups according to their sex,age,and season,at which the disease occurred. Results: The detection rate of duodenal bulbar ulcer was17.14% in male cases,8.22% in female cases,18.16% in cases with their age ≤30 years,13.75% in cases at the age of 31-40 years,16.04% in cases at the age of 41-50 years,13.92% in cases at the age of 51-60 years,and 7.11% in cases with their age over 60 years,respectively.The detection rate of duodenal bulbar ulcer was 12.17% in Spring,11.59% in Summer,20.34% in Autumn,and 11.44% in Winter,respectively.The detection rate of duodenal bulbar ulcer was higher in males than females,in cases with their age under 60 years than in those with their age above 60 years（P＜0.01）,in Autumn than in the other three seasons（P＜0.01）. Conclusion: The detection rate of duodenal bulbar ulcer is significantly higher in males than females,in cases with their age under 60 years than in those with their age over 60 years,in Autumn than in the other three seasons.