The "black bone and muscle" is cardinal melanin trait of black bone sheep. The black bone sheep and the native sheep in Lanping and Luomuni sheep were chosen as materials for the measurement of TYR activity of blood and melanin content of tissues and organs. Moreover, we compared characteristic structure of melanin of black bone sheep with silky fowls. The results showed as follows: TYR activity was significantly different between black and non-black bone sheep (P<0.05); the total character of infrared spectrum (IR) of melanin of black bone sheep resembled silky fowls; and melanin was eumelanin. We firstly cloned exon1 667bp sequence of TYR gene and determined TYR gene polymorphism of black and non-black bone sheep by PCR-RFLP. Compared with sequence of TYR gene of non-black bone sheep, there were two nucleotide mutation sites in exon1 of black bone sheep, located in No.64 and No.154 amino acid codons, respectively; but they were synonymics mutation. We designed restriction site in codon 64 and check up TYR gene polymorphism. The result showed the mutation site together with the close linked gene influenced melanin trait deposition. It suggests there should be functional mutation related with melanin trait. Furthermore, there was significant correlation between TYR gene polymorphism and coat color of sheep (P<0.01), indicating TYR could influence synthesis of coat color of sheep.