Abstract： Severe periodontitis is the main cause of tooth loss in adults, with varying degrees of horizontal and vertical alveolar bone loss. In view of the complex alveolar bone defect, a suitable surgery planning should be made on the basis of fully understanding the characteristics of alveolar bone defect in severe periodontitis and the key points of bone augmentation technique, so as to choose an appropriate method for reconstruction of alveolar bone and complete the implantation and restoration to ensure the integrity of dentition, which are important for the long-term stability of periodontal health. Based on clinical experiences and literature review, we summarizes the characteristics of alveolar bone loss in patients with severe periodontitis and the timing of implant placement after bone augmentation surgery, in order to provide reference for implant treatment of severe periodontitis.