Abstract: The aim of this study was to investigate the expression laws of bone morphogenetic protein 2 （BMP2）gene in the development skin hair follicles of Inner Mongolia Cashmere Goat in a complete period and the effects of implanting melatonin （MT）on its expression. Eight female mature Inner Mongolia Cashmere Goats were randomly divided into 4 groups. MT in group 1- 3 was implanted in animals （test groups） and the fourth group in which MT was not implanted was control group. The samples of skin from lateral part were collected during one year to detect the expression of BMP2 gene in developmental stage of hair follicles by real-time quantitative PCR. The results showed that the expression amount of BMP2 gene in prosperous period and resting period of hair folliele＇s development was slowly increased and the expression amount in resting period was higher than that in growing period. The expression amount of BMP2 gene in resting period was reduced after implanting MT and there was no significant difference of the expression amount during the whole growth period. The expression amount of BMP2 in the skin of Inner Mongolia Cashmere Goat was closely related with the periodic growth of hair follicles. The expression model of BMP2 gene in the growth period of hair follicles was changed after implanting MT. It was speculated that BMP2 gene might be involved in regulating the growth and development of skin hair follicles in Inner Mongolia Cashmere Goat.