Abstract: AIM To prove whether ischemic preconditioning is protective against myocardial ischemia. METHODS Myocardial tissues were obtained from models of three groups in different periods and immunohistochemical method was used to detect the expression of cTnT. The depletion areas of cTnT in myocardial infarction were measured under the microscope by the computer image analysis and the results were analyzed by statistical methods. RESULTS The depletion areas of the control group, the preconditioning group and the infarction group increased gradually in the same period and the result was significant. CONCLUSION Ischemic preconditioning is protective against myocardial ischemia.