Abstract: Objective To establish whether serum levels of tumor necrosis factor（TNF）-α could be modified by surgical periodontal treatment. Methods 35 moderate to severe chronic periodontitis patients who had undergone basic periodontal treatment were chosen. They were randomly divided into two groups. Periodontal surgery was performed in the experimental group while supportive periodontal therapy was administered in the control group. Clinical parameters including probing depth（PD）, plaque index（PLI） and circulating serum TNF-α levels were assessed at baseline and 16 weeks following treatment in both groups. Results PD, PLI and the levels of TNF-α all have statistically significant reduction in the experimental group compared with the control group（Р <0.05）. Conclusion Surgical periodontal therapy can reduce the TNF-α levels in serum and the periodontal clinical indices.