Objective To survey the current status of pubertal development of urban school-age children in Yiwu,and to compare the difference between Yiwu and national level. Methods Totally 1 026 school-age children (578 male,448 female) were selected from 2 schools in urban area of Yiwu city from September to October 2016.The height,weight,waist circumference (WC),hip circumference(HC) and sexual maturation states (Tanner stages:breast stages for girls and testicular volume for boys) of children and adolescents were measured. Results 1) Breast development at B2 period of 9 years old group was observed in 18% of girls,B3 and above period was observed in 11.5%; Testicular development began of 10 years old group was observed in 8.9% of boys,G3 and above period was observed in 1.1%; 2)The prevalence of overweight and obesity was 16.1% and 13% in girls,the prevalence of overweight and obesity was 7.2% and 12.6% in boys;3) Testis volume was positively correlated with age,height,body weight,BMI and waist circumference,and age was the strongest correlation;4)The proportion of sexual development in overweight and obesity group were higher than in normal group of boys and girls in all age groups. Conclusion The sexual development level of school-age children in Yiwu is higher than the national average level,it is worthy for people to pay attention on this point.