Objective To test the level of 25-hydroxyl vitamin D [25(OH)D] in children with central precocious puberty (CPP), and to analyze the correlation between sex hormones and 25(OH)D. Methods A total of 182 CPP children diagnosed in endocrinology department were enrolled in this study in 2015, and 200 health children at the same age were selected as control group.Plasma level of 25(OH)D was tested by electrochemical analysis, and the correlation between 25(OH)D level and luteinizing hormone (LH)/peak follicle-stimulating hormone (FSH) were analyzed. Results The level of 25(OH)D was significantly lower in CPP group than that in control group [(55.7±16.9) nmol/L vs.(66.5±20.1) nmol/L, t=5.70, P<0.05].The level of 25(OH)D was negatively related to LH/FSH peak(r=-0.74, P<0.05).The proportion of vitamin D deficiency in CCP group(39.7%) was significantly higher than that of control group(22.2%), while the proportion of vitamin D sufficiency(16.3%) was significantly lower than that of control group(33.3%) (P<0.05). Conclusions Because of the early bone growth and development of children with early puberty, vitamin D is in high demand.So in the treatment of sexual precocity, the importance of vitamin D should be strengthened, and regular monitoring of 25(OH)D levels and vitamin D supplements are recommended.