Abstract: Objective The periodontitis, with a morbidity of 70%-85%, seriously endangers oral health. It is urgent to explore a new effective periodontal treatment method. Subgingival air polishing has the characteristics of high comfort, safety and high efficiency in periodontal treatment. The purpose of this study is to evaluate the clinical effect of subgingival air polishing technology for moderate and severe chronic periodontitis. Methods Thirty-six patients with moderate to severe chronic periodontitis were selected from August 2016 to March 2018 in the Department of Periodontal Mucosa, Affiliated Stomatological Hospital of Anhui Medical University. The data of periodontal exploration one week after supragingival air scaling were taken as baseline data. The principle of oral control design was adopted. One side of the same patient's teeth was randomly designed as experimental group, subgingival air polishing was performed, and the other side as control group, ultrasonic subgingival scaling was performed. After three months, the clinical indicators were reviewed by periodontal exploration. VAS pain score was used to assess the pain level of the two groups. Results The difference in plaque index (PLI), bleeding index (BI), probing depth (PD) and attachment loss (AL) between the two groups in baseline was not significant. Three months after treatment, the above indexes were improved as compared with the data in baseline, but the difference was not significant between the two groups (P>0.05). The pain score of VAS immediately after the treatment in the experimental group was lower than that in the control group (P<0.05). Conclusion During the three-month follow-up period, subgingival air polishing achieved the same effect as ultrasonic subgingival scaling for moderate and severe chronic periodontitis patients, and could reduce patients' discomfort.