Objective To evaluate expression of E-cadherin and COX-2 in placentas of hypertensive disorder complieating pregnancy,and study the relationship between them.Method The E-cadherin and COX-2 of twenty-one cases gestational hypertension,along with 17 cases preeclampsia,and 20 cases normal pregnancy placentas were investigated by immunohistochemistry.Results The expression of E-cadherin was significantly higher and the expression of COX-2 was lower in preeclampsia cases than that in normal pregnancy(P＜0.01).The expression of E-cadherin negatively correlated with the expression of COX-2 (r=-0.371.P＜0.05).Conclusions The alteration of E-cadheria and COX-2 in placentas are correlated with preeelampsia.The up-reguhted expression of E-cadherin and down-regulated expression of COX-2 maybe regulated by the same factor.