The effects of tyrosine on the formation of melanin in Guyuan silky fowls were studied to investigate the characteristics of the distribution and deposition of melanin in Guyuan silky fowls， and the changes in the expression of melanin-related gene under different content of tyrosine in diet. 150 healthy Guyuan silky fowls at 4 weeks of age with no significant difference in body weight were randomly divided into 5 groups， with 3 replicates in each group and 10 chickens in each replicate. The content of tyrosine added in diet was 0， 0.2%， 0.4%， 0.6%， and 0.8%， respectively， and the fowls were fed until the end of 12 weeks of age. The electron microscopy was used to observe the characteristics of the distribution of melanin in different tissues of Guyuan silky fowls. The immunohistochemistry and fluorescence quantitative PCR method were used to detect changes in the expression of melanin-related genes in different tissues of Guyuan silky fowls. The results showed that there were melanocytes in the skin， trachea， and small intestine of Guyuan silky fowls， and most of them were differentiated and matured. TYR had a positive reaction in lung tissue， TYRP1 had a positive reaction in muscle and liver tissue， and MITF and CREB1 had positive results in lung， liver， small intestine， and breast muscle tissue. The expression level of MITF， TYR， and TYRP1 gene was linearly correlated with the content of melanin under different content of tyrosine in diet. It is indicated that the characteristics of melanin deposition in tissues of Guyuan silky fowls are related to the amount of melanin granules synthesized in the tissues， and TYR and MITF may be the main key regulatory genes during the synthesis of melanin. Adding tyrosine to the diet can promote the expression of melanin-related genes.