Objective To analyze the clinical application effect of hydraulic sinus floor elevation combined with Bio-Oss-Collagen bone graft in the treatment of maxillary posterior tooth loss. Methods A total of 60 patients with maxillary posterior tooth loss admitted to the Department of Stomatology, Changle County People’s Hospital from June 2023 to March 2025 were selected, and they were divided into the control group and the observation group according to different surgical graft materials, with 30 patients in each group. Both groups underwent hydraulic sinus floor elevation. The control group was given Bio-Oss graft, and the observation group was given Bio-Oss-Collagen bone graft. The surgical success rate, excellent and good rate of implant-bone interface adaptation, alveolar ridge height and marginal bone loss around implants were compared between the two groups. Results The surgical success rate of the observation group (100.00%) was higher than that of the control group (80.00%) (P <0.05). The excellent and good rate of implant-bone interface adaptation in the observation group (100.00%) was higher than that in the control group (80.00%) (P <0.05). The alveolar ridge height at 6 and 12 months after operation in the observation group was higher than that in the control group (P <0.05). The marginal bone loss around implants in the observation group at 6 and 12 months after operation was less than that in the control group (P <0.05). Conclusion For patients with maxillary posterior tooth loss, hydraulic sinus floor elevation combined with Bio-Oss-Collagen bone graft can improve surgical success rate and excellent and good rate of implant-bone interface adaptation, and maintain favorable alveolar ridge height.