Objective A 3-D solid model of a human maxillary first molar was constructed and exported into a 3D-finite element model with analysis of the stress distribution of the tooth. Methods Using the CT scanning of a normal adult, with the help of the computer program and software, a 3D finite element model was established. Three different loading conditions were simulated: vertical, lateral occlusal loading and both of them. Result Stress concentration were found on the surface where the load was applied, and at the lingual cervical part of the crown when the stresses arising from sideways and combination. Conclusion The method of this study can construct a relatively accurate model of the tooth, and provides a reasonably simple and effective model for biomechanical analysis of the molar applications.