Chronic periodontitis is the most common type of periodontitis, accounting for approximately 95% of patients with periodontitis, and is caused by the expansion of long-standing chronic gingivitis into deep periodontal tissues. The treatment of chronic periodontitis should focus on plaque control, basic periodontal treatment, surgical treatment, and improvement of chewing function. 1, control of plaque: so that the plaque area affected by chronic periodontitis is less than 20% of the tooth surface, and assist systemic treatment, the preferred drugs are macrolides and metronidazole. 2.Basic periodontal treatment: use scaling or scraping to thoroughly remove the tartar on or under the gingiva, remove the stains attached to the tooth surface, and can use root planing to scrape the diseased tooth bone. 3.Surgical treatment: After the perfect periodontal basic treatment still remains greater than or equal to 5mm of periodontal pockets and probing bleeding, or encounter difficult to remove the tartar can be used to treat chronic periodontitis. Surgical procedures include removal of tartar and granulation tissue, revision of the shape, and periodontal guided tissue regeneration. 4.Improve chewing function: fix loose teeth, extract worthless teeth as early as possible, etc. 5.Other: treatment of systemic diseases, smoking cessation, regular review and maintenance. Long-term adherence to treatment and regular maintenance is one of the key conditions for the treatment of chronic periodontitis. Therefore, it is necessary to adhere to plaque control and regular review to prevent recurrence.