The mean friction coefficient on tooth surface was calculated under mixed elastohydrodynamic lubrication based on Bloks flash temperature formula. Furthermore, the mean friction coefficient of the formula was modified, and the formula was improved. Meanwhile, through calculating the tangential velocity, half width of Hertz contact zone and load distribution factor along the meshing point of spiral bevel gears, the formulas to calculate the flash temperatures along the contact path and whole tooth surface of spiral bevel gears under mixed elastohydrodynamic lubrication were proposed respectively, which provided a comprehensive and accurate method for its calculation of scuffing load capacity. The results of analyzing the calculation example indicated that the maximum flash temperature along the contact path located in the middle recess path, and the one of the whole tooth surface was between the pitch cone and dedendum of gear, where the scuffing failure showed the most possibly.