Low cutting forces can signi cantly reduce the risk of damage to sensitive tissues adjacent to the bone. Because of its better control of the incision, lower cutting force and reduced postoperative complications, the application of ultrasonic tools in bone-cutting is of concern to surgeons. In this study, through the application of a full factorial design of experiments, the e ects of changes in cutting tool geometry, ultrasonic power, bone-cutting direction, and tool speed on the cutting forces of cortical bone are assessed simultaneously. The variance and regression of the experimental data are analyzed, and the impact of factors and interactions of the elements on the cutting forces are discussed. The adjusted coe cient of determination (R 2 adj) of the main cutting force and cutting resistance force of the statistical model were 91. 49% and 91. 15%, respectively. Both the blade geometry and ultrasonic power, together with their interactions, are the most in uential factors in the cutting forces, contributing 82. 2% and 86. 6%, respectively. The formation of teeth in the cutting edge improves the cutting process and reduces the cutting force by about 40%. To obtain high e ciency and low cutting force, it is recommended to use an ultrasonic-powered toothed edge blade with a pitch of 1 mm, a low vertical velocity, and a high longitudinal speed.