Abstract: Objective：To study the stress distribution after pterygomaxillary implantation in posterior maxillary alveolar by using three-dimensional finite element method. Methods：In six models with dentition defects in the posterior maxillary region, tilted implants were placed at 45° to occlusal plane (45° tilted implantation) or at 70° to Frankfort plane (70° tilted implantation) and constructed fixed bridges with normal implants in the premolar maxillary region. The static force of 200N was vertically loaded on the second molar or first molar of the fixed bridges to analyze the stress distribution in the posterior maxillary alveolar bone. Results：①The stress of alveolar bone was 43.18 17.15MPa after 200N vertical force loading to 70° tilted implantation while it was 67.25 18.44MPa in 45° tilted implantation. ② The stress of alveolar bone was about 32.49 19.01MPa when 200N vertical force loading to the second molar of fixed bridges constructed with the 70° tilted implant and normal implant while the stress was about 26.89 14.66MPa when 200N vertical force loading to the first molar of the fixed bridges. ③ The stress of alveolar bone was about 39.88 17.12MPa when 200N vertical force loading to the second molar of fixed bridges constructed with the 70° tilted implant and normal implant while the stress was about 31.03 15.05MPa when 200N vertical force loading to the first molar of the fixed bridges. Conclusion: The pterygomaxillary implantation was applied to repair dentition defects in the maxillary posterior region, 70° tilted implantation with the single crown or fixed bridge could be selected according to the abutment puncture point. The 45° tilted implantation should be combined with mesial implants or natural teeth to form fixed bridge to avoid biological complications caused by the stress exceeding the limit of alveolar bone tissue.