Abstract: AIM:To observe the clinical effect of low molecular weight heparin (LMWH) compared with unfractionated heparin (UFH) in intra-aortic balloon pump (IABP) surgery. METHODS: Sixty-eight patients with IABP were randomly divided into two groups: conventional group (34 cases) using UFH anticoagulation and observation group (34 cases) using LMWH anticoagulation. The incidence of bleeding, hematoma, thrombosis and other complications, as well as the cost in the two groups, were recorded. RESULTS: Only slight wound bleeding, local small hematoma and mild bruising around the wound were observed in a low percentage of the patients, with no significant difference between groups. However, the cost in the observation group was significantly lower than in the conventional group. CONCLUSION: LMWH has a low cost and is more convenient and if as effective as UFH in regard to anticoagulant and antithrombotic effect for IABP.