〔Abstract〕 Objective To explore the effects of different implant sites combined with pterygomaxillary implantation on the biomechanics of implant and bone tissue, and to provide a basis for clinical selection of implant design in accordance with biomechanical principles. Methods The cone-beam CT scan data of an edentulous maxillary with inadequate posterior bone were selected to complete the establishment of the three-dimensional entity model of the maxilla. The prosthesis and implant-abutment integrated three-dimensional entity models were established using the prosthesis and implant data, and five groups of three-dimensional finite element models of different implant sites were designed. A unilateral vertical load of 200 N and an oblique load of 100 N were applied to the bilateral posterior dental area, respectively. ANSYS finite element analysis software was used to calculate the stress distribution on the surface of the implant and surrounding bone tissue. SPSS 26.0 software package was used to statistically analyze the data. Results (1) All the five models showed that the maximum stress was concentrated in the neck of the implants and cortical bone.(2) The maximum stress value of the implant under oblique loading was greater than that under vertical loading(P<0.05), but there was no significant difference in the maximum stress value around bone tissue in the 5 groups of models.(3) There was no significant difference in the maximum stress of the implant and bone between the different implant sites combined with pterygomaxillary implants. Conclusion In the fixed restoration of maxillary edentulous implants, pterygomaxillary implants implanted symmetrically on both sides and changing the position point of the anterior implant do not affected the stress distribution of the whole design. In clinical practice, suitable sites can be selected according to the residual bone mass of patients, and combined with pterygomaxillary implantation for implant design.