Subgingival calculus is primarily removed by subgingival scraping. Subgingival curettage is the use of a relatively fine subgingival curette to scrape away the tartar located on the root surface of the periodontal pocket. Subgingival scraping is operated in the periodontal pocket, the naked eye can not be visualized, so before scraping should first explore the shape and depth of the periodontal pocket, the amount of subgingival tartar and site, to find out the situation before scraping. When scraping the subgingival tartar in deep periodontal pockets, some of the granulation tissue on the inner wall of the pocket should be scraped at the same time. The operation in deep pockets may cause different degrees of pain, and thus deep pocket scraping should be performed under local anesthesia. If subgingival calculus is present, it is recommended to visit the hospital promptly for targeted treatment or therapy under the guidance of the doctor.