Abstract: Abstract: Objective To study the effects of clenbuterol on levels of LDH and antioxidant capacity of myocardium in mice. Methods The health mice were chosed and administered different dose of clenbuterol by intraperitoneal injection for 30 days. After 30 days the mice’s heart were isolated and homogenated, the levels of ATP, SOD, MDA, and GSH-PX were detected. Results The enzyme activity of ATP, SOD and GSH-PX seemed to be reduced, while the levels of MDA tended to be elevated with the increase of clenbuterol dosage. Conclusions Clenbuterol could decrease myocardial ATP enzyme activity and antioxidant capacity, which could result in myocardial injury.