Objective To evaluate the therapeutic effect and the mechanism of dextran microsphere hepatic artery embolization for hepatoma. Methods Partial hepatectomy was performed in 11 patients with hepatoma pretreated with dextran microsphere hepatic artery embolization. All specimens were for histopathologic studies in order to observe the destiny of dextran microspheres and necrotic degree of the tumor. Results complete necrosis of the tumor was found in seven cases and incomplete necrosis of the tumor in the rest 4. Tumors in the later were near to areas rich in arterial collateral anastomoses. The extent of tumor necrosis was unrelated to the presence and thickness of tumor capsule and capsular invasions. Dextran microspheres could cause permanent embolization of distal arterioles. The microspheres were very biocompatible and cause little foreign body reaction. No inflammatory changes were seen both inside and outside of the embolized artery 191 days after embolization. Dextran microspheres were not absorbed and the vessel recanalization was also not seen. Dextran microsphere was not found in portal veins. Conclusion Some hepatomas distant from the collateral circulation of arteries could be cured with dextran microsphere hepatic artery embolization alone.