Objective    To research the influence of anticoagulation to blood clotting function in patients who experienced cardiopulmonary bypass surgery under continuous renal replacement therapy (CRRT) with regional citrate anticoagulation (RCA), low molecular weight heparin (LMWH) anticoagulation and non-anticoagulation. Methods    We retrospectively analyzed the clinical data of 146 patients who underwent CRRT after cardiopulmonary bypass surgery between January 2014 and December 2016. There were 98 males and 48 females at age of 60.51±14.29 years. All CRRT patients were allocated into three groups including a RCA group, a LMWH group, and a non-anticoagulation group, which were compared in terms of convention coagulation tests, platelet counts, thromboelastography, circuit lifespan and transfusion. Results    Three hundred and fifty four CRRT patients were selected from patients above, including 152 patients in the LMWH group, 160 in the RCA group, and 42 in the non-anticoagulation group. The difference of CRRT circuits time among three groups was statistically different (P=0.023). And multiple comparison showed that the circuit lifespan of the RCA group was significantly longer than that of the non-anticoagulation group (34.50 h ranged 14.00 h to 86.00 h vs.15.00 h ranged 12.00 h to 50.88 h, P=0.033). One hundred and fifty-five CRRT patients last beyond 24 hours  with same anticoagulation were selected, the results of coagulation tests, and the difference between CRRT starting and after 24 hours were compared. The difference of Angle and maximum amplitude(MA) of pre- and post-CRRT were significantly different among three groups by one-way ANOVA (P=0.004, 0.000), as well as between the RCA group and the LMWH group by multiple comparison (P=0.004, 0.000). There was no statistical difference in frequencies and doses of the transfusion of fresh frozen plasma and platelet among three groups. Conclusion    RCA is an effective anticoagulation which may prolong circuit lifespan and has small impact on the coagulation function of patients who undergo CRRT after cardiopulmonary bypass surgery.