Abstract: Objective To establish the serum insulin reference intervals in Chinese adults. Methods 10027 individuals were recruited and undertook questionnaires, physical examinations and Laboratory measurements in an epidemiological study. Finally, the insulin reference intervals were established with 1433 apparently healthy subjects who were justified as reference individuals. Results The difference of insulin levels were existed between male and female, while no correlation of insulin levels was observed with age in the healthy. Conclusion The insulin levels can be influenced by gender, and the gender-related insulin reference intervals for Chinese adults could provide valuable information for physicians in the diagnosis and treatment of diabetes.