Objective To compare the differences of effects of enoxaparin and unfractionated heparin on the extrinsic coagulation system and activity of platelet in patients with unstable angina pectoris and non-ST-elevation acute myocardial infarction and the predictive value of two types of heparins for the occurrence of clinical events. Methods Selected cases were divided into the enoxaparin group and unfractionated heparin group. Levels of anti-Ⅹa factor, von Willebrand factor (vWF), free tissue factor pathway inhibitor (free-TFPI) were detected at different time points before and after administration. The correlation of detected indexes and clinical events of patients was analyzed. Results The anti-Ⅹa level of the enoxaparin group reached the efficient level 3 h after administration; remained within the efficient range at 3 h time point 48 h after administration; and was significantly higher than that of the unfractionated heparin group (P<0.05). The vWF level of the enoxaparin group was significantly lower than that of the unfractionated heparin group (P<0.05). The ⊿vWF of patients with clinical events was significantly higher than that of patients without clinical events (P<0.01). The ⊿vWF was relevant to clinical events occurring within 30 d (OR=1.373, P<0.05). Conclusion Compared with unfractionated heparin, enoxaparin can block the extrinsic coagulation pathway and prevent the platelet adhesion and aggregation more efficiently. The increase of vWF in early stage may be used to predict clinical events occurring within 30 d for patients with unstable angina pectoris and non-ST-elevation acute myocardial infarction.