Object: To study the outcomes of GnRHa on final adult height in Chinese idiopathic central precocious puberty (ICPP) girls and the involved factor(s) that can predict height gain. Methods: We conducted a retrospective analysis on 10 years of data obtained from three clinical hospitals from January 2005 to March 2015, and 101 girls with ICPP, who received GnRHa therapy for more than six months and already reached their adult height were enrolled. Results: Height, bone age, midparent height, HtSDS, sexual development, therapy duration and predicted adult height(PAH) at start and end of GnRHa, and the final adult height(FAH) were recorded and calculated. Their PAH significantly increased at end of GnRHa (158.4 +/- 6.00cm), compared to that at the start of GnRHa(153.1 +/- 5.37cm) (P< 0.001), and their final adult height(157.0 +/- 4.82) significantly increased compared to PAH at start of GnRHa(P< 0.001). There was no difference between PAH at end of GnRHa and FAH(P> 0.05). After GnRHa therapy, most of the ICPP girls reached their midparent height compared to that at start of GnRHa(P< 0.01). FAH was positively correlated with Ht at start, and end of GnRHa, PAH at start and end of GnRHa, and also with midparent height (R-2= 0.59, 0.74, 0.68, 0.73 and 0.80, P< 0.001). While FAH was not correlated with the duration of treatment and BA at start of GnRHa(R-2 = 0.15and 0.1, P> 0.05). The percentage of adult short stature decreased and those reached midparent height significantly increased after GnRHa therapy, compared to that at start of GnRHa(60.6% vs. 30.4% and 67.85% vs. 94.64%, respectively, P< 0.05). Conclusions: GnRHa therapy to ICPP girls can effectively achieve the final adult height. After GnRHa therapy, most of these patients reached their midparent height, while few of these patients had an adult short stature.