Abstract: To study the effects of α-Melanocyte Stimulating Hormone(α-MSH)on the proliferation and melanin synthesis of cultured Alpaca skin melanocytes．The cultured Alpaca skin melanocytes were treated with various concentration of α-MSH(0, 10^-9, 10^-8, 10^-7 mol·L^-1)in vitro. The effects of α-MSH on proliferation, melanin contents, MC1R, MITF and TYR gene expression of cultured melanocytes were observed. Three days after treatment with αMSH, the number of melanocytes increased and melanin contents, MC1R, TYR gene expression level also remarkably increased in treated cells compared to those in untreated cells(P＜0.05), especially when the concentration was 10^-8 mol·L^-1, and MITF gene also remarkably increased(P＜0.05)when the concentration was 10^-7 mol·L^-1.α-MSH can induce the dendrites elongated, proliferation, melanin synthesis and the expression of MC1R, MITF and TYR of alpaca skin melanocytes.