This study develops a new lobe pump rotor profile that significantly improves pump performance. Rotor profiles including two traditional designs and two new designs consist of three segments that are generated by circular or/and epicycloidal curves. This study evaluates the performance of four profiles via volume calculation and flow field analysis, considering to the number of lobes. Results demonstrate that the shapes of rotor surfaces affect pump performance remarkably. An epicycloidal profile provides a much advantage than a circular profile. The new rotor profile with three segments was generated by the curves in order of epicycloidal-circular-epicycloidal (ECE profile) obtained performance of 55% higher than the traditional profiles and the order of circular-epicycloid-circular (CEC profile). The analysis in this study also proves that a multi-lobe design of three or four lobes does not increase pump performance, but provides a more stable output and higher capacity than a two-lobe pump.