An experimental model was used to determine the changes in TNF, MDA and SOD in granulation tissues during natural wound healing after skin excision on rats. Our results indicated that the changes in TNF and SOD exhibited a curve of V. The levels of TNF and SOD were lower on day 7 than day 3. The levels of MDA rose gradually, especially on day 7. A positive correlation was shown between TNF and MDA (at days 3, 5, 7), also between TNF and SOD (at day 3, 7). When the concentration of TNF was lower than 90 Pg/mg protein, the process of wound healing was best, while wound healing was hindered when the levels of SOD were low. The results suggest that in the process of wound repair there are influential changes in the contents of TNF, MDA and SOD. Lower levels of TNF and higher levels of SOD are apparently beneficial to wound healing after trauma.