Abstract: Objective To investigate the onset age of sexual development in children with idiopathic short stature，to study the gonadotropin levels in children with idiopathic short stature of different gender and age，and to explore whether the gonadotropin-releasing hormone（GnRH）stimulation test can be simplified. Methods The clinical data of children with idiopathic short stature who were hospitalized in the Department of Endocrinology of Wuhan Children's Hospital from 2013 to 2020 were retrospectively collected. The median ages of female breast developing to B2 stage and male testicular developing to 4 mL were calculated. The differences of basic value，30，60，90，120 min and peak value of luteinizing hormone（LH）and follicle stimulating hormone（FSH）in GnRH stimulation test of different gender，age and sexual developing stage were analyzed，and the differences of results at different measurement time points were compared. Results ① The median age of female breast developing to B2 stage was 10. 42 years old，and the median age of male testicular development to 4 mL was 12. 08 years old. ② The peak value of LH in boys increased significantly at 9 years old，and the mean value of peak value was more than 5 mIU/mL at 10 years old，the peak value of LH in girls increased significantly around 10 years old. The basic value of LH in both boys and girls increased significantly at 11 years old. The basic value of FSH increased gradually from school age. The peak value of FSH decreased with the increase of age in girls，and was higher than that of males in all age groups. ③ Regardless of sex development，the LH average value of girls was the highest at 30 min，and that of boys was the highest at 60 min. There was no significant difference between 90 and 120 min （P = 0. 095 in prepuberty group and P = 1 in puberty group）. The highest mean value of FSH in girls was at 60 or 90 min，and there was no significant difference between 60 and 90 min（P = 1 in prepuberty group and P = 0. 225 in puberty group）. Conclusion ① The onset age of puberty in children with idiopathic short stature is about 10. 42 years old for girls and 12. 08 years old for boys，which is slightly later than the previous large-scale survey data of healthy children. ② In the GnRH stimulation test，the peak of LH mostly appeared in 30 - 60 min，while the peak of FSH mostly appeared in 60 - 120 min. No matter male or female and no matter what the sexual development stageis，the values of LH at 30 min and LH at 60 min can better reflect the peak level of LH，and the value of FSH at 90 min can better reflect the peak level of FSH. ③ The GnRH stimulation test was simplified to 0，30，60 and 90 min，which could well reflect the peak of LH and FSH.

Key words: short stature, children, sexual development, gonadotropin-releasing hormone stimulation test