率高达83.4%。The technology of obtaining androstenones (AD) from phytosterol by microbial degradation in biphasic systems and the effects of substrate concentration, surfactants and 9α-hydroxylase inhibitor on biotransformation were studied by experiment. The results show that sunflower oil-aqueous biphasic system is the most suitable for bioconversion, and the concentration of substrate and low-concentration of 9α-hydroxylase inhibitor can increase the rate of biotransformation to a certain extent. Finally, the sunflower oil-aqueous biphasic system of fermentation is optimized by orthogonal experiment, and the optimal condition is as following: systems with the concentration of 20% sunflower oil, 0.4% substrate and 0.005% HgCl2. Under this condition the transformation rate of AD is 83.4%. 