Background: During puberty, gray matter volume decreases and white matter volume increases in brain. It has been suggested that pubertal hormones may induce some neuroanatomical changes during puberty. Central precocious puberty (CPP) is caused by premature activation of the hypothalamus-pituitary-gonadal axis in inappropriately early age. However, little is known about the differences of brain structure (especially brain volume) in idiopathic CPP. Also the relation between luteinizing hormone (LH) and brain morphology in CPP remains unclear. Objective and hypotheses: This study aimed to evaluate the difference of brain structure in idiopathic CPP, age-matched healthy control, and the normal puberty girls, and the association between LH and brain structure. Method: The study enrolled fifteen girls with idiopathic CPP, 15 age-matched healthy girls and 15 normal puberty girls as controls. The subjects underwent on a 1.5 Tesla Avanto MR Scanner. Anatomical T1-weighted images were acquired with a T1 spin echo sequence. MR image data were processed by using SPM8 with DARTEL algorithm. Results: The mean age of CPP, age-matched group and puberty group were 8.0±0.9 year, 7.8±0.9 year and 11.9±0.9 year. Compared with controls, CPP showed a significant increase in gray matter (GM) volume of the left cerebellar cortex, and in white matter (WM) volume; the left superior temporal lobule (STL), right middle temporal pole (MTP) and left lingual gyrus (LiG) (p0.001). Especially, the WM volume of the STL (r=0.56), MTP (r=0.56) and LiG (r=0.57) was positively correlated with LH concentrations (p0.05). Conclusion: Regional GM and WM volumes were increased in girls with idiopathic CPP compared with age-matched and pubertal controls. The growth of white matter might be directly or indirectly mediated by LH production in idiopathic CPP. These data suggest that the presence of early sexual maturation-related variations in structure of developing brain of girls with idiopathic CPP.