As a new diluted magnetic semiconductor, vanadium-doped ZnSe is theoretically predicted to induce ferromagnetism above room temperature without carrier doping. Vanadium-doped ZnSe was epitaxially grown on (100) GaAs substrate by metal-organic vapor phase epitaxial method in an atmospheric pressure. As a dopant source of vanadium, triethoxyvanadyl was used. The influences of molar supply ratio of dimethylzinc to dimethylselenide on crystallinity were investigated in order to research the optimum vanadium-doping condition. The crystal growth condition of vanadium-doped ZnSe changed from epitaxial growth to polycrystal growth at molar supply ratio between 1.2 and 1.5.