Purposes: To investigate the outcomes of gonadotropin-releasing hormone agonist (GnRHa) alone and those of combined growth hormone (GH) therapy for the girls with idiopathic central precocious puberty (CPP), we analyzed their height gain at the end of treatment and after the closure of growth plate. We calculated and compared the changes of the predicted adult height ( PAH) during the treatment with GnRHa with and without GH in girls with CPP. Methods: For this retrospective study, data were collected for the 119 girls with CPP who were treated with GnRHa for 36 months or more, from 2002 to 2016. We assessed the changes in PAH standard deviation score (SDS) and height gain SDS in groups received GnRHa alone (Goup A, n=85) or GnRHa combined GH (Group B, n=36) following up more 2 years later, after cessation of therapy. The calendar dates of their menarche were asked and recorded. Results: In the Group A, the initial height SDS (0.73±0.90 vs -0.21±0.67, P 0.001) and mean parental height (MPH) SDS (-0.36±0.60 vs -1.07±0.72, P0.001) were significantly higher than those of the Group B. The annual growth velocities (GV) of the Group B were higher than GV of the Group A (Group A vs Group B; 6.10±0.94 cm vs 6.87±1.69cm at first year, P=0.002; 5.53±0.95cm vs 6.33±1.70cm at second year, P=0.001; 5.07±1.01cm vs B 5.73±1.37cm at third year, P=0.004). The treatment duration was longer in Group B than Group A (Gr. A 44.98±9.49months vs Gr. B 49.58±15.11months, P=0.045). Near final height(NFH) SDS was not statistically significantly different (Gr. A 0.67±1.09 vs Gr. B 0.38±0.64, P=0.151). The differences between NFH SDS and initial PAH SDS (that means height gain SDS) of both groups were not statistically significant (Gr. A 2.71±1.0 vs Gr. B 2.38±0.93, P=0.116). The differences between NFH SDS and target height (MPH SDS) were larger in Group B than that of Group A (Gr. A 1.00±0.97 vs Gr. B 1.40±0.78, P=0.034). The term of observation for achievement of adult height from the end of therapy were 31.55±23.97 months. The height gain SDS was statistically positively correlated with MPH SDS ( P=0.012) and initial height SDS ( P0.001). Conclusion: The girls treated with GnRHa and GH showed faster growth velocity and could completely catch up with those treated with GnRHa alone.