Abstract: It was reported that p-coumaric acid (Ⅰ) exerted excellent interceptive activity in pregnant mice, and based on the fact that some aryl substituted styrenes also showed certain extent of antifertility effect, thus twenty four derivatives of α-phenyl or naphthyl p-coumaric acid (Ⅱ1-24) were synthesized for evaluation of their antifertility activity. According to preliminary pharmacological test, four compounds Ⅱ_(1,3,7,23) exhibited significant effects on termination of early pregnancy in mice at the single oral dose of 50mg/kg of body wt/day(P<0.05～0.001),among them, compound Ⅱ_1 was most active (P<0.001).