Objective:To preliminarily explore the synthesis of a quercetin derivative 3′,4′,5,7-four-(O-methoxy carbonyl meth-yl) quercetin and its pharmacological activities. Methods:Quercetin as the reactant and N,N-dimethyl-formamide ( DMF) as the sol-vent, the target product 3′,4′,5,7-four-(O-methoxy carbonyl methyl) quercetin was obtained by the slow addition of methyl chloroace-tate in the presence of anhydrous K2 CO3 to introduce ether bond at 3′,4′,5,7- bit. The structure was characterized by LC-MS, 1 H-NMR and element analysis. The nanoemulsion of the product was prepared using a film dispersion method, and with intraperitoneal in-jection, the effect on pituitrin-induced myocardial ischemia cardiovascular system in rats was observed. Results:3′,4′,5,7-Four-(O-methoxy carbonyl methyl) quercetin was successfully synthesized, and could be metastasized to a demethylation product containing dis-tal free carboxyl with increased polarity proved by metabolic tests in vitro. The results of electrocardiogram and animal experiments showed that the compound had improving effects on pituitrin-induced myocardial ischemia in rats. Conclusion: The nanoemulsion of 3′,4′,5,7-four-(O-methoxy carbonyl methyl) quercetin with intraperitoneal injection shows significant antagonism against pituitrin-in-duced myocardial ischemia in rats.