Objective: To establish percentile reference values and curves of body mass index (BMI) for children and adolescents aged 7~17 in Jiangsu Province, providing a scientific basis for evaluation of growth and development characteristics. Methods: Based on the “Surveillance for common disease and health risk factors among students project”, a stratified random cluster sampling method was used to collect 45,595 students aged 7~17 from 26 counties (cities or districts) of 13 cities in Jiangsu Province. BMI percentile reference values for children and adolescents in Jiangsu Province were obtained by using the skewness-median-coefficient of variation method (LMS method). The corresponding percentile curves were fitted and compared with the national level. Results: The BMI of boys and girls aged 7~17 in Jiangsu Province increased with age. Boys' BMI enters the growth peak at the age of 9, slows down after the age of 12, girls' BMI enters the growth peak at the age of 10, and slows down after the age of 14. The 5th, 50th, and 95th BMI percentiles of children and adolescents in Jiangsu Province were higher than the national level throughout the age range. Conclusion: This study presents the distribution of BMI among children and adolescents in Jiangsu Province; BMI percentile reference values and growth curves of children and adolescents in Jiangsu Province were obtained based on the LMS method, and the fitting effect was good. The main percentiles of BMI for boys and girls in all age groups in Jiangsu Province were higher than the national level, and the median BMI for boys in each age group was higher than girls.