Three-dimensional stress freezing method of photoelasticity was used to analyze internal stress distribution on the alveolar bone of the abutment with a complete fixed bridge under three kinds of occlusal loads.A three-dimen-sional model was used to represent a missing mandibular first permanent molar.The ratio of the model and prototype was1.The results showed that the direction of occlusal loads exerted an direct influence on the mag-ni tude of the stress of the alveolar bone.The horizontal static load might lead to stress concentration in the alveolar crest while the vertical load could result in the greatest stress in the corresponding alveolar crest and apex of a single root..The stress distribution of supporting bone around molar root was most equal,regardless of loading form.The molar is an ideal abutment tooth for a fixed bridge.