Abstract: Objective To observe the INR of AF hyperuricemia patients' prothrombin time under the situation where both allopurinol and warfarin are used to the treatment of anticoagulation.Methods A total of 240 patients with chronic permanent AF hyperuricemia were collected and then divided randomly into two groups:warfarin treatment group (120 cases), to maintain the original dose warfarin therapy and keep a low-purine diet; and the combined treatment group(120 cases), also in the conventional warfarin antithrombotic therapy and a low-purine diet, on this basis, plus allopurinol 100 mg, three times a day, which last for two weeks. Then observing and examining the change of the two group's INR after the treatment.Results The INR of the combined treatment group was obviously higher than the warfarin group(P<0.05).Conclusion Allopurinol can increase antithrombotic effect of warfarin. INR should be monitored regularly during the treatment so as to adjust warfarin dosage accordingly.