We investigated the mechanism of apoptosis induced by shock vibration in canine peripheral lymphocytes, the T-lymphocyte changes, and the expression of p53 and bax gene products related to apoptosis using the techniques of immuno- and enzyme cytochemistry. We noted obvious apoptosis after delivery of 80, 100, and 200 acceleration of gravity values (G values). The percentage of apoptotic lymphocytes was directly proportional to the G value. On the 3rd day after injury, the number of apoptotic lymphocytes reached the peak value, which was about 5 to 8 times the amount in the control group. On the contrary, on day 3 after injury, T lymphocytes decreased and were about 50% of the control group. On the other hand, we found that the percentage of p53 and bax-positive lymphocytes distinctly increased and, on the 3rd day after injury, their number was, respectively, about 2.3 and 1.8 times that in the control groups, suggesting that they may play an important role in lymphocyte apoptosis. The above-mentioned results provide an important basis for further study of the mechanism of shock-vibration injury, its prevention, and treatment.