Ｏｂｊｅｃｔｉｖｅ　To explore the clinical effect of preoperative autologous plateletpheresis and back-transfusion in off-pump coronary artery bypass grafting (OPCABG).　Methods　Thirty two patients undergoing OPCABG were randomly divided into 2 groups(n=16)： control group(group A) and acute platelepheresis group (group B). In group A, intraoperative autotransfusion was applied. In group B, combined acute normovoemic hemodiltion and autologous platelet-rich plasma back-transfusion and intraoperative autotransfusion were applied. Hb, platelet count(Plt), prothrombin time(PT), activated partial thromboplastin time(APTT) and fibrinogen(Fib) were measured before anesthesia induction(T0), pre-heparinization(T1) and at 1, 24 h after operation(T2, T3). Postoperativ drainage volume at 1 and 24 h after operation were recorded.　Results　In group B, volume of the whole blood for acute plateletpheresis was (1 100±145) ml. Volume of platelet?蛳rich plasma(PRP) collected was (166±30) ml. Plt of the PRP was (1 010±210)×109/L, accounting for (26±3)% of the total number of platelet in the whole blood volume. Compared with group A, the Plt at 1 h after operation was obviously higher in group B. The drainage volume at 1, 24 h after operation was obviously reduced in group B. Less allogeneic RBC were transfused in group B than group A. Coagulation tests showed no significant difference in both group.　Conclusions　Preoperative acute plateletpheresis and back-transfusion in OPCABG can ruduce the amout of allogenic blood transfusion and postoperative blood loss and blood transfusion costs, meanwhile can avoid blood transmitted diseases and transfusion reaction.