Abstract: This paper studies the myosin Ca++-ATPase activity of Bufo gargarizans cardiac muscles and gastrocnemius muscles.The experimental results imply that the changes of myosin Ca++-ATPase activity of B.gargarizans cardiac muscles and gastrocnemius muscles take place depending on the active law of theirs in different season,and artifical low temperature has no effect on above changes.In addition,the myosin Ca++-ATPase activity of cardiac muscles is consistently higher than of gastrocnemius muscles in different season.These changes of Ca++-ATPase activity are important for physiological actions.