To observe the effect of oxidative stress reaction in miniature pig PCI perioperative myocardial injury (PMI) process, and discuss the mechanism of Yiqi Zhuyu Shen Yuan Dan (SYD) on myocardial injury. Methods: Twenty-four Chinese miniature pigs were randomly divided into four groups, namely, control group(n=6), model group(n=6), SYD low dose group［0.06 g/(kg·d) n=6］, SYD high dose group ［0.24 g/(kg·d), n=6］. Balloon dilatation, injury and stenting were used to make PCI pig models. Serum creatine phosphokinase isoenzyme (CK-MB), troponin I(cTNI) and superoxide dismutase (SOD), malondialdehyde (MDA) and reducing glutathione (TSH) were detected and compared before 1 hour of surgery and after 4hr, 12hr, and 24hr of surgery. Results: No statistical differences were found among groups in pre-operation cardiac enzyme levels (P>0.05), while after treatment, myocardial enzyme increases, while less than 5 times the normal reference value. It indicated the success of building injury models. Myocardial enzyme levels at each time point in SYD low dose group, high dose after surgery were lower than those of the model group, and the difference is statistically significant (P<0.05). After 12 hr, 24 hr, myocardial enzyme level in SYD high dose group is lower than that of SYD low dose group, and the difference is statistically significant (P<0.05). Compared with control group, SOD and GSH levels in the model group decreased while the MDA level increased with statistical difference(P<0.05). SOD and GSH levels in model group has decreased than pre-operation, while MDA increased, with statistical difference(P<0.05). SOD and GSH levels in the SYD low dose and high dose group increased and MDA levels decreased, with statistically significant difference(P<0.05). However, 4 hours after surgery, statistical differences showed between SYD high dose group and low dose group(P<0.05), and high dose group is superior to low dose group. Conclusion: Chinese miniature pig PMI models are successfully built, and Shen Yuan Dan has improved PMI endogenous myocardial injury. SYD high dose group has better performance than low dose group, which indicates the protective function of Shen Yuan Dan may relate to different does. Oxidative stress factor varied before and after the surgery, which may involve with the development of PMI. Shen Yuan Dan can accelerate the generation pace of anti-oxidation factor, maintain its effective concentration, and thus to reduce oxidation factor. This could possibly be its protective mechanism.