Objective To explore the clinical value of measuring myoglobin (MYO) for the early diagnosis of ACS and monitoring the effect of thrombolysis. Methods MYO and cTnT, CK、CK-MB were measured. The sensitivity, specificity, positive predicting value and negative predicting value of cTnT and CK-MB at different time points were studied. And the correlation was investigated between the MYO plasma level and the severity of coronary artery lesion according to coronary arteriongraphy. The changes of MYO level with thrombolysis were also observed. Results The concentration of MYO, cTnT, CK, CK-MB in acute myocardial infarction patients were (56?34)?g/L, (0. 05?0. 03 )?g/L,(94?84) U/L,(17?13) U/L respectively, which were higher than that in the healthy controls(P 0. 05). The level of MYO rises to the peak at 5. 26 hours after operating thrombolysis. The peak time was earlier than CK and CK-MB (P