Abstract: A novel elliptical arc-rotor of claw vacuum pump was proposed,based on the meshing principle,to solve the problems of the existing arc-rotors,such as the trouble-some cusps and large clearance volume.First,the meshing and envelope of elliptical arc-rotor were mathematical formulated; next,its profile and parametric equation were derived; and finally,the influence of the key radius ratios,defined herein as μ,ε and ζ,on the distributions of pressure/flow-field inside the pump and the distributions of stress/deformation of the arc-rotor,was theoretically analyzed with standard k-ε turbulence model and numerically simulated in finite element method(FEM).The simulated results show that the newly-developed elliptical arc rotor outperforms the existing circular arc-rotor and arc-rotor with cusps,because of higher pumping efficiency,weaker stress and less deformation.