In order to explore expression of the PNA receptor in early myocardial infarction, immunohistochemical technique was performed (S-P method). The expression of the PNA receptor occured in the early acute cardiac ischemic area induced experimentally by ligation of left coronary arteries of 32 SD rats. The following changes on myocardial cell membranes at the ischemical areas were found. Positive staining of PNA could be observed in ischemic area at 15min after ischemia, and it increased along with the prolongation of ischemic period. It became the strongest after is chemic 2h and then decreased. This may be of some value in forensic medicine practice.