Several photoelastic materials with different ingredient proportions of firming agent were made up. Freezing elastic ratios of materials were measured by the YE2538 programmable static strain gage. According to the elastic modular ratio of the steel-copper worm gears, suitable materials for worm gears photoelastic model were selected. The worm photoelastic model was made in the way of steel mandrel surrounded with epoxy resin tooth, and the gear was made by the method of integral cast. Worm gears photoelastic model was assembled in the reduction box, and the load was applied by a torsion bar, and stress freezing was finished in the oven. Stress-difference line distribution property of sections of worm gear was observed on the photoelasticimeter 409-Ⅰ. At last, the result of photoelastic method and the result of the finite element method (FEM) were compared. The result shows that differences of the maximum fringes value among the meshing teeth are minuteness, and secondary primary stress difference at the dedendum and the addendum of the tooth is larger than that near the pitch. In conclusion, the reliability of the photoelastic experiments of the worm gears is confirmed.