Objective: To study the effect of imbalance between lysosomal enzymes and their inhibitors in blood on disturbance of the local and whole body after trauma. Methods: The dynamic changes of lysosomal enzymes and proteinase inhibitors were studied in 12 pigs with femoral comminuted fractures in both hind limbs caused by high velocity missiles. Four normal pigs served as controls. Results: After injury, the activity of Cathepsin D in arterial plasma increased gradually and reached the highest level at 8 hours, acid phosphatase in serum began to increase at 12 hours and the value of serum elastase did not change significantly. The level of α1-antitrypsin, a proteinase inhibitor in plasma, decreased significantly in the early stage after injury [73.5%±6.4% and 81.0%±5.1% of the baseline value (1.67 μmol*ml-1*min-1± 0.29 μmol*ml-1*min-1) at l and 2 hours after injury, respectively, P<0.05], then increased gradually and was higher than the baseline value at 12 hours after injury. Conclusions: Imbalance between lysosomal enzymes and proteinase inhibitors occurs soon after injury, which might result in continuous tissue damage and play an important role in the disturbance of general reaction after injury.