OBJECTIVE： To compare clinical efficacy， safety and economy of urokinase and alteplase each combined with Enoxaparin sodium in the treatment of acute ST segment elevation myocardial infarction （STEMI）.  METHODS： 80 STEMI patients were randomly divided into control group and observation group， with 40 cases in each group. Both groups received Aspirin enteric-coated tablet for antiplatelet aggregation， and Clopidogrel hydrogen sulfate tablet for anticoagulation before thrombolysis. Control group were given urokinase 1 500 000 U added into 0.9％ Sodium chloride injection 100 ml， ivgtt， within 30 min； given Enoxaparin sodium injection 7 500 U intramuscularly 12 h after thrombolysis， for 3-5 d. Observation group was given Enoxaparin sodium 60 U/kg， ivgtt， 1 mg/ml Alteplase for injection 8 ml with intravenous push， other 42 ml ivgtt within 90 min； continued to receive Enoxaparin sodium with 12 U/（kg·h） micro-pump for 48 h， followed by Low molecular weight heparin calcium injection 5 000 U intramuscularly， bid， for consecutive 5 d. Clinical efficacy of 2 groups were observed， and thrombolytic recanalization situation were observed 30， 60， 90 and 120 min after thrombolysis. ECG， cost-effectiveness and ADR were also observed. RESULTS： The effective rate of observation group （92.50％） was significantly higher than that of control group （85.00％）. The rates of thrombolytic recanalization in observation group 60， 90 and 120 min after thrombolysis were significantly higher than in control group， with statistical significance （P＜0.05）. Q wave time， Qwave/Rwave and ST segment deviation of observation group after treatment were significantly lower than those of control group， with statistical significance （P＜0.05）. The total hospitalization cost of observation group was significantly higher than that of control group， with statistical significance （P＜0.05）； there was no statistical significance in effective rate and the per unit cost of thrombolytic recanalization rate （P＞0.05）. The incidence of ventricular aneurysm， pericardial effusion， heart failure or cardiac shock， angina pectoris after infarction， severe arrhythmia， death and other aspects in observation group were significantly lower than in control group， with statistical significance （P＜0.05）. CONCLUSIONS： Alteplase and enoxaparin thrombolysis therapy is better than urokinase and enoxaparin for STMEI in respects of clinical efficacy， and thrombolytic recanalization with less ADR and better safety； urokinase is cheaper and better than alteplase in cost-effectiveness ratio. Both of them can be used after careful consideration.