Objective: The aim of the present study was to ascertain the effect of mandibular jaw shape on stress distribution in implant-bone interface. Methods: Three-dimensional finite element analysis (3D FEA) was used in this study. Six models with different mandibular jaw shapes were set up. Axial and lateral forces were loaded on the models. The stress values and distribution patterns in the different models were compared. Results: Stress values under lateral loads were much higher than under axial loads. The stress distribution patterns were similar in the six models and there was no evident difference in stress value. Conclusions: Lateral occlusal forces should be reduced in clinical implants supporting prostheses. The effect of mandibular jaw shape on stress distribution in implant-bone interface can be ignored. It is rational to simplify the mandibular jaw shape in FEA study.