This study was carried out to determine the curative effect of low-intensity anticoagulant therapy by observing the oral administration of warfarin (anticoagulant therapy) on patients who had undergone mechanical heart valve replacement (MHVR) surgery with subsequent anticoagulation complications. Fifty patients who underwent MHVR in the Second Affiliated Hospital of Harbin Medical University and 52 patients in the Cardiovascular Surgery of Daqing Oilfield General Hospital between January 2013 and January 2016 were selected (63 males and 39 females, ages 26-77 years). They took warfarin after treatment and were followed-up by means of outpatient review and telephone after leaving the hospital. The effect of warfarin and the occurrence of anticoagulation complications were analyzed. The operations lasted 230±106 min, extracorporeal circulation for 110±50 min and aorta occlusion for 82±23 min. During post-operation 3 patients developed skin purpura and one patient died. During follow-up we found 3 cases of anemia caused by excessive menstruation, 4 cases of hematuresis, 3 cases of peated epistaxis, 1 case of gastrointestinal bleeding, 1 case of cerebral hemorrhage, 1 case of embolism in the lower limbs and 1 case of cerebral infarction, although they all improved or were totally cured. Therefore, the incidence of complications can be reduced significantly by the correct administration of warfarin as well as timely monitoring of interference factors after MHVR.