Objective：To observe the changes of serum bone formation markers such as amino-terminal pro-C-type natriuretic peptide（NT-proCNP），bone alkaline phosphatase（BAP），osteocalcin（OC） and insulin-like growth factor-1（IGF-1） in girls with idiopathic central precocious puberty（ICPP），so as to explore the relationship among them. Methods：A total of 100 ICPP girls and 100 healthy controls were collected in the study. The serum bone formation indicators（NT-proCNP，OC，BAP and IGF-1） were measured by ELISA. SPSS 26.0 was used for relevant statistical analysis. Results：①The levels of NT-proCNP，OC，BAP and IGF-1 in the ICPP group were higher than those of the normal control group（all P<0.05），and serum NT-proCNP and IGF-1 levels in Tanner Ⅱ were higher than those in the stage Ⅲ（P<0.05）. ② The difference between bone age and chronological age in girls with ICPP was negatively correlated with NT-proCNP and positively correlated with IGF-1. ③Characteristics of ROC curve showed that serum NT-proCNP，OC，BAP and IGF-1 had certain diagnostic value for ICPP，and IGF-1 had the highest sensitivity and specificity. ④After six months of treatment with GnRHa，the levels of NT-proCNP，OC，BAP and IGF-1 in ICPP were all lower than those before treatment（all P<0.05）. Compared with the normal control group，the concentrations of NT-proCNP，OC and IGF-1 in blood were not statistically different，while the concentration of BAP in blood was still higher in ICPP after six months of treatment with GnRHa. Conclusion：Serum levels of NT-proCNP，OC，BAP and IGF-1 can indirectly reflect the growth and development of girls with ICPP，so it is partly valuable for early diagnosis of ICPP. We suggest that these indexes may be used to observe the therapeutic effect of ICPP.