Abstract： Objective To study the relation of cytochrome P450 expression and pregnancy induced hypertension. Methods Compared the changes after inhibition of cytochrome P450 expression, to evaluate the function of cytochrome P450 in pregnancy induced hypertension with blood pressure measure, fetus development and western blot. Results Comparing with control group, the blood pressure increase ( 118.6 ± 8 ) vs (95.1 ±7 ) mm Hg,P ＜ 0. 05 ) , the weight and length of fetus, and the weight of placena decrease ( 1.8 ± 0. 39) vs( 2. 76±0.61)g,(1.78 ±0.32)vs(3.04±0.58)cm,(0.38 ±0.12)vs(0.45 ±0.15)g,P＜0.05),western blot showed the expression of CYP2C23 was inhibited by MSPPOH in plancta. Conclusion These results demonstrated the inhibition of CYP2C23 expression was the cause of fetus retardation. Downregulation of cytochrome P450 expression might be the mechanism of pregnancy induced hypertension.