Objective To investigate the effect of bone grafting or not on implant stability following simultaneous implantation with maxillary sinus floor elevation. Methods A total of 82 patients undergoing implantation surgery at the Department of Stomatology, South Campus of Afffliated Hospital of Jiangnan University from November 2023 to November 2024 were selected. According to whether bone grafting was performed, they were divided into the control group (no bone grafting) and the observation group (bone grafting), with 41 patients in each group. Both groups received simultaneous implantation with maxillary sinus ffoor elevation. The implant stability quotient (ISQ), implant survival rate, height of new bone formation at the sinus floor, residual bone height, elevation height and complication rate were compared between the two groups. Results There was no statistically signiffcant difference in the excellent and good rate of ISQ between the two groups (P>0.05). There was no statistically signiffcant difference in implant survival rate between the two groups (P>0.05). At 3, 6, and 12 months after operation, the height of new bone formation at the sinus ffoor in the observation group was higher than that in the control group (P<0.05). The residual bone height in the observation group was lower than that in the control group, and the elevation height was higher than that in the control group (P<0.05). The incidence of complications in the observation group (4.88%) was lower than that in the control group (19.51%) (P<0.05). Conclusion In patients with maxillary posterior tooth loss treated by simultaneous implantation with maxillary sinus ffoor elevation, implant stability and survival rate are similar whether bone grafting is performed or not. Bone grafting promotes bone tissue regeneration at the maxillary sinus ffoor, facilitates new bone formation, and helps to increase both residual bone height and elevation height.