Objective To observe and evaluate the protective effect of desflurane post?conditioning on myocardial injury during cardiopulmonary bypass and its influence on patients' postoperative recovery. Methods A total of 200 patients in need of cardiac surgery were selected as the experimental subjects， who were aged from 20 to 65 years old， and divided into ASA Ⅱ-Ⅲ and NYHA Ⅱ-Ⅲ by endotracheal intubation and extracorporeal circulation method under general anesthesia. The patients were randomly divided into desflurane post?treatment group （experimental group， group D） and control group （group C） after selection. With the successive opening of the aorta and superior vena cava， group D were given 5% desflurane by inhalation with mechanical ventilation. While group C inhaled pure oxygen without inhaling desflurane. The depth of intraoperative anesthesia was maintained between 40 ~ 50 during the operation. Radial artery blood was collected from patients in 24 h before surgery （T0）， immediately after intubation （T1）， and 1 h（T2）， 6 h （T3）， 12 h （T4） and 24 h （T5）after aortic opening to achieve the determination of troponin I （cTnI） and creatine kinase isoenzyme MB （CK?MB）.On the premise of obtaining the informed consent of the patient， about 50 mg of right atrial appendage tissue was collected before aortic intubation （T1.5） and 1 hour after aortic opening （T2） to determine the apoptosis rate. Results （1）cTnI in group C at the time of T2， T3， T4 and T5 was apparently higher than group D （P < 0.05）. （2）CK?MB in group C at the time of T3 was apparently higher than group D （P < 0.05）. （3）The myocardial tissue results showed that there was a lower apoptosis rate in experimental group at the time of T2 （P < 0.05）. Conclusion Desflurane post?conditioning has a myocardial protective effect during cardiac surgery under cardiopulmonary bypass.