Abstract: Objective To observe the effect of low molecular heparin as an anticoagulant on hemoperfusion for acute poisoning. Methods Patients with acute poisoning treated in the Second People's Hospital of Linhai City from November 2008 to December 2013 were divided into unfractionated heparin(UH) group and low molecular heparin (LMH) group, with 60 patients in each. Before and after hemoperfusion, the blood coagulation function (APTT, PT, and TT), platelet (PLT), perfusion apparatus, catheter blood coagulation and bleeding of the patients were observed and compared between the two groups. Results Before and after treatment,PLT, APTT, PT and TT of the patients in LMH group were not of significant difference (all P>0.05). After treatment, PLT decreased as well as APTT, PT, and TT prolonged among the patients in UH group, and the differences were statistically significant(all P<0.05). The incidence of catheter coagulation was 11.67% in UH group and 1.67% in LMH group. The incidence of bleeding was 18.33% in UH group and 5.00% in LMH group. The differences between the two groups were statistically significant(all P<0.05). Conclusion Low molecular heparin with stronger anticoagulation activity does not cause bleeding easily in hemoperfusion. It is the preferred anticoagulant, and the conventional coagulation test after hemoperfusion is not necessary.