Abstract: A novel algorithm was developed to quantitatively evaluate the minimized weight and maximized flow-pulsation coefficient of the Roots vacuum pump and/or blower with high-profile rotor.First,the analytical equations of the key variables,including the flow pulsation,volume utilization,volume per-unit displacement and high-profile shape coefficients,were rigorously derived.Next,the influence of the independent variables,such as the basic shape coefficient,lobe-number and half lobe-top angle,on the rotor profile was investigated; and finally,the minimal weight and maximal flow-pulsation coefficient were mathematically modeled.The calculated results show that the high-profile rotor outperforms the basic rotor.We suggest that the two variables may best evaluate the optimal weight & pulsation,including the narrowest allowable half lob-top angle and the smallest volume per-unit displacement,limited by the largest allowable flow pulsation coefficient.