Abstract: On the basis of Tooth Contact Analysis (TCA) and Loaded Tooth Contact Analysis (LTCA),an approach to calculating the maximal tooth contact stress course in the whole meshing period of spiral bevel gears has been provided,by using the theory of elasticity.The effects of tooth surface geometry,load share,tooth deformation and manufacturing errors on contact stress course could be shown by means of the approach.An optimal method for high tooth contact strength was presented,in which by controlling the shape and amplitude of the transmission error curve,that is the curvature on tooth height,the maximal contact stress could be reduced and an improved contact strength could be obtained.