Objective To investigate the clinical characteristics, TCM syndrome differen tiation and short_term prognosis of painless acute myocardiac infarction (AMI). Methods Restrospective analysis was carried out in 32 patients with painless AMI (Group A) and 30 cases of painful AMI in the same period served as Group B. Results In Group A, clinical manifestations were latent, infarct places mai nly located in the inferior wall, right ventricle and posterior wall of the hear t ( 65.6% ), and yang_Qi deficiency syndrome and Qi_yin defic iency syndrome occupied 65.6% of painless AMI. Blood stasis syn drome and phlegm syndrome occupied 70.0% of painful AMI. The co ncurrent incidence of diabetes mellitus was higher in Group A than Group B. So d id the mortality and the incidence of heart failure. Cardiogenic shock and heart failure were the main death causes of painless AMI. Conclusion The above r esults will supply evidence for the combined treatment of painless AMI.