Three lactoproteins (α-Sl-casein, β-lactoglobulin, and β-casein) promotors were cloned, sequenced and compared relative luciferase expression. The results showed that the promotor activity of bovine α-S1-casein gene was the best, and would be used to produce pharmaceutically and medically important proteins in the mammary gland of transgenic animals and also for the construction of an inducible eukaryotic expression vector.