Abstract: A novel type of segmented circular Roots rotor, comprising three arcs in the addendum portion, was proposed. The equations, of the dedendum curves conjugating with the addendum curves, were derived in the meshing theory, and the profile of the rotor was mathematically modeled. The conditions of non-undercutting and zero carryover of the segmented circular Roots rotor were analyzed. The influence of the dimensions of rotor profile on the area utilization coefficient was investigated. The calculated results show that the central-angle of the rotor's profile has a major impact. To be specific, with the fixed radii of outer-circle and pitch-circle, as the central-angle increases, the area utilization coefficient increases. In addition, the area utilization coefficient of the newly-developed segmented circular Roots rotor was found to be higher than that of the conventional circular Roots rotor.