Objective To explore the dynamic changes and clinical value of bone metabolic index after gonadotrophin releasing hormone analogue (GnRHa) treatment in girls with central precocious puberty(CPP),in order to provide scientific reference for clinical treatment. Methods Totally 36 CPP girls treated with GnRHa and 36 healthy girls as controls were enrolled in this study from October 2015 to June 2016,and were tested for serum bone mineralogy,bone formation and common serum levels before treatment and 6 months,12 months,18 months and 24 months after treatment. Bone resorption marker levels were compared in groups and different time points. Results At the end of the study,the observation group lost 5 (13.89%) cases,and the control group lost 4(11.11%) cases. There were no significant differences on blood Ca,P,25-(OH)D₃ and β-CTX between CPP group and control group at each time point after treatment (P＞0.05). Blood E2,N-MID OC,P1NP and BALP decreased gradually after treatment,and there was statistically significant difference between CPP group and control group at each time point (P<0.05). Conclusions Estrogen level in children is significantly reduced during the first 12 months of treatment with GnRHa. And the effect of GnRHa on osteoblasts is more pronounced than that on osteoclasts.