Abstract: In this paper, for gear couple with stepped-double-circular-arc H-2 type tooth profile, from measurement by a strain gauge of 0.2mm on gear test stand with locked-in torque, the root stress variation curve along tooth length on both tensile and compressive side with different load as well as the root stress induced by loading the gauged tooth alone or by loading neighboring tooth were obtained. The equations of realationship between stresses and loads for this tested gear couple were derived. Those results may be as reference for strength calculation and basic rack design of gear couple with double-circular-arc tooth profile.