The purpose of this study was to search the sensitivity of three indicators in early diagnosis of acute myocardial infarction (AMI) and analyze their window-time duration in serum, along with the decision on experimental golden indicator in later AMI inspection and effect assessment after recovery by testing the concentrations of CTnI, CK-MBmass and Mb in AMI patients' serum. By using corpuscle chemiluminescence, the serum concentrations of CTnI, CK-MBmass and Mb in AMI patients, UA (unstable angina) patients, SM (skeletal muscle) patients and a normal group were assayed and compared. A dynamic analysis was followed in five periods, which separately focused on 3-5, 8-14, 20-24, 72 hours and 7 days after heart aching occurred in AMI patients. The results showed the positive rates of CTnI, CK-MBmass and Mb in AMI patients were 65%, 70% and 70% respectively, and the positive rate of CTnI in UA and SM groups was 0%. The CTnI, CK-MBmass and Mb values in group AMI were significantly higher than those in groups of UA and SM. Separately, the CTnI value in AMI was 84 and 91.63 times (the CTnI values) in UA and SM; the CK-MBmass value in AMI was 8.82 and 4.67 times and the Mb value in AMI was 11.57 and 2.25 times as high as those in UA and SM. Significant difference was observed by the comparison between AMI group and UA, SM groups (P < 0.001). According to the dynamic analysis, CTnI, CK-MBmass and Mb rose significantly at the early stage of AMI onset (3-5 hrs), and then gradually increased with time. The climax occurred in the period of 8-14 hrs and Mb returned to its normal state in 72 hrs. On the 7th day, CTnI still existed in serum, but CK-MBmass approximated to normality. In conclusion, these data demonstrate a relatively high sensitivity of CTnI, CK-MBmass and Mb in early diagnosis of AMI. CTnI is specific to cardiac muscle for its special positive rate. Also, CK-MBmass and Mb are of higher clinical value in diagnosing cardiac muscle damage. CTnI has the longest window-time, which makes it the best special indicator for terminal inspection and recovery decision on AMI.