Aiming to investigate the effects of tea polyphenols on the mitochondrial apoptosis cascade reaction mediated by mitochondrial oxidative stress and tenderness of yak meat during postmortem aging. The longissimus dorsi muscles injected with inhibitor tea polyphenol were taken as the experiment objects. The levels of mitochondrial oxidative stress, degree of mitochondrial oxidative damage, mitochondrial functional characteristics, process of mitochondrial apoptosis and change of meat tenderness in the control group and the treatment group were measured. The results showed that the level of mitochondrial ROS, MDA and carbonyl content in the treatment group was overall significantly or extremely significantly lower than that in the control group in the early of postmortem aging. At the middle and late of aging time, the SOD activity and the mitochondrial membrane fluidity was significantly or extremely significantly higher than that in the control group. After 24h, opening of the MPTP in the treatment group was significantly or extremely significantly lower than that in the control group. After 6~168h, the Cytc concentration of mitochondria in the treatment group was higher than that in the control group; during 72~168h, the Cytc concentration of cytoplasm in the treatment group was significantly or extremely significantly higher than that in the control group. Meanwhile, Caspase3 activity and MFI in the treatment group was significantly or very significantly lower than that in the control group at early aging time. The research demonstrated that tea polyphenols inhibited the role of the mitochondrial apoptosis cascade reaction on the meat tenderization by inhibiting ROS mediated oxidative stress damage of mitochondrial structure and function. These observations indicated that tea polyphenols acted as the antioxidants and antistaling agent in improving the quality of meat at the same time, may have adverse effects on meat tenderization from the angle of the mechanism of apoptosis tenderization and further confirmation was needed.