Objective To investigate the effect of warfarin on coagulation and hemorheology in patients with atrial fibrillation.Methods 106 cases of admitted in our hospital from October 2014 to October 2016 were randomly divided into observation group(53 cases)and control group(53 cases).The control group re-ceived routine treatment,the observation group received routine and warfarin treatment.The two groups were treated for 4 weeks.The therapeutic effects were compared between the two groups.Before and after treat-ment,indicators of heart function,blood coagulation and hemorheology were observed.Results The total effi-ciency of observation group(92.45%)was higher than that of the control group(73.58%,P<0.05).After treatment,the TT and APTT of the two groups both increased(P<0.05);The TT and APTT of the observa-tion group were higher than that of the control group(P<0.05);The plasma viscosity,erythrocyte aggrega-tion index,and fibrinogen of the two groups decreased(P<0.05);The plasma viscosity,erythrocyte aggrega-tion index,fibrinogen of the observation group were lower than that of the control group(P<0.05).Conclu-sion Warfarin has obvious curative effect on patients with atrial fibrillation,and can improve the function of blood coagulation and hemorheology.