Objective To investigate the effect of internal maxillary sinus lifting technique in patients with maxillary posterior dentition defect. Methods A total of 104 patients with maxillary posterior dentition defect repaired by oral implant in Xianyang Stomatological Hospital from February 2021 to December 2022 were selected as the study objects, and were divided into control group and observation group by random number table method, with 52 patients in each group. The control group was treated with traditional implant repair, and the observation group was treated with internal maxillary sinus lifting technique. The treatment efficiency, complication rate, surgical index, satisfaction, quality of life, oral bleeding index, plaque index and bone absorption around the implant were compared between the two groups. Results Thetotal effective rate of the observation group was 98.08%, which was higher than that of the control group 76.92%, the difference was statistically significant (P<0.05). The incidence of complications in the observation group was 3.85%, which was lower than 23.08% in the control group, and the difference was statistically significant (P<0.05). The treatment time and masticatory function recovery time of the observation group were lower than those of the control group, and the difference was statistically significant (P<0.05). The satisfaction level of observation group was higher than that of control group (P<0.05). The quality of life score of the observation group was higher than that of the control group after intervention, and the difference was statistically significant (P<0.05). There was no statistical significance in the bone absorption volume around the implant between the two groups (P>0.05). The oral bleeding index and plaque index of the observation group were lower than those of the control group, the difference was statistically significant (P<0.05). Conclusion Internal maxillary sinus lifting technique can achieve satisfactory results in the treatment of patients with maxillary posterior dentition defect, reduce the incidence of complications, shorten the time of surgical treatment, and improve the oral bleeding index of patients.