Objective: To compare body composition of girls aged 10 to 15 years with or without onset of menarche in Nanyang, and to provide a reliable basis for effective adolescent health care. Methods: From August to December 2020 and from March to October 2021, cluster random sampling was adopted in 13 areas of Nanyang City to select 1 523 girls. Questionnaire survey and body composition (Japan Bailida MC-180) were conducted. Results: BMI, body fat percentage, trunk fat percentage, muscle mass and bone mass of girls aged 10 to 15 years in Nanyang City gradually increased with age, the water content in the body decreased with age. BMI, fat percentage, trunk fat percentage, muscle mass and bone mass in girls experienced menarche were higher, while water content in the body was lower than those without menarche. Significant difference in BMI between the menarche and without menarche of girls were found in those aged 11 to 15 years( t =2.07, 2.03, 2.43, 2.45, 2.52, P <0.05). Significant differences in fat rate, trunk fat rate, muscle mass and bone mass between the menarche and without menarche were found in girls aged 12 to 15 years fat percentage, trunk fat percentage muscle mass bone mass( P <0.05). Among girls aged 10, 14 and 15 year old, significant difference in body water percentage were observed in the two groups of girls with or without menarche( t =2.75, 2.35, 2.37 , P <0.05). Average age at menarche showed significant urban rural differences among girls aged 10, 11 and 14 year old ( χ 2=4.34, 3.45, 6.73, P <0.05). Conclusion Changes in body composition including BMI, body fat percentage, muscle mass, bone mass and body water percentage during the transition to menarche in girls is helpful to predict menarche in girls. Age of menarche is related to nutritional status, BMI, physical exercise, snack and beverage intake.