Abstract: This study aims to clarify the quantitative effects of four arc contour configurations of Roots rotors (Configuration A: center of the top shaft; Configuration B: center of the outer central shaft on the pitch circle; Configuration C: center of the inner central shaft on the pitch circle; Configuration D: center of the root shaft) on product performance and the medium adaptation and selection requirements. First, based on a unified contour construction equation, UGNX software was used to quantify rotor blade attributes such as blade cross-sectional area and centroid radius. Then, Pumplinx software was employed to conduct CFD (computational fluid dynamics) simulations for low-viscosity air (at 1000 rpm) and high-viscosity water (at 400 rpm). Finally, multi-dimensional performance was analyzed. The results show that the order of blade attributes and theoretical flow characteristics is B > C > A > D. Compared with Configuration A, the moment of inertia of Configuration B decreases by 23.0% and the theoretical displacement increases by 4.26%. Under low-viscosity conditions, Configuration A has the highest cost-performance ratio, while Configuration C has the largest leakage. Under high-viscosity conditions, Configuration D achieves the optimal cost-performance ratio (1.4% higher than that of Configuration A), and Configuration B exhibits extremely significant pressure fluctuations caused by extrusion and expansion. The four rotor configurations show significant differences in performance, and their selection must match the medium viscosity: Configurations B and C are preferred for low-viscosity media, while Configurations A and D are preferred for high-viscosity media, supplemented by small radial dimensions and low rotational speeds.