Objectives:to compare the stress distribution of dental supporting structures of a tilted mandibular molar before and after the restoration of three-unit fixed partial denture (mandibular second premolar to second molar) and to evaluate the influence of different tilting angle on the stress distribution of the molar abutments using finite element analysis.Methods:Six three-dimensional finite element models of 3-unit fixed partial dentures in which the second molars were tilted 0, 15 ,30 ,40 ,50 and 60 degrees toward the second premolar and one model with unrestored second molar of 30 degrees were constructed by the combination of the Computed Tomographic (CT) scanning technology and Ansys software.All models were meshed with 8-node tetrahedral elements into over 460,000 elements and 80,000 nodes. A vertical load of 25kg was applied to the second molar on the central fossae in each case.Compare the stress distribution between models with different tilting angles and between restored and unrestored models with the angle of 30 degrees.Results:the magnitude of stress distribution around the roots of the abutments was increased with the increase of tilting angle.And the stress increased significantly with the angle of 40 degrees©zP£¼0.05©{,and the introduction of a fixed partial denture decreased the stress in the bone mesial to the root and adjacent to the apex of the tlted molar and increased the stress surrounding the second premolar. Conclusion:the stress distribution in the supporting structures around the roots of the tilted molar abutments was modified by the placement of the fixed bridge,but If the tilting angle was over 40 degrees,the fixed bridge was not recommended from the aspect of biomechanics only since it may cause high stress concentration and do harm to the supporting tissue.