A rotor configuration design for the new turbo booster pump which is combined a TMP section with a spiral-groove rotor by a specially designed connecting blade and is proposed by Jou et al.@footnote 1@ and this new design is successfully predicted by both of CFD and DSMC methodologies simultaneously. The computed and tested results show that this pump is effective to operate in an inlet pressure range from 10-7Torr to around 10Torr with a maximum pumping speed approximately 1000L/s in free molecular regime. To investigate the inner pressures and to compare the computed data with experimental one, a measurement system also has been constructed.@footnote 2@ Since the aforementioned rotor geometry is composed of three different sections, a TMP section, a connecting section, and a spiral groove section, respectively, it is very difficult or even impossible to efficiently design the rotor geometry and to optimize its performance. In this paper, rotor geometries with characteristics of varied helical angle and groove depth are modeled using two design curves. These curves can be expressed by two appropriate functions, like polynomials, to meet the different pumping requirements in each different regime. The channel of the rotor is then modeled by the rule surface generated from the two characteristic design curves. Through this geometrical representation, pumping speed and compression ratio for this pump also can then be evaluated by the same computational scheme and same design procedure as previous paper. Analyses are conducted to parameters of the curves to show the optimization of the design. @FootnoteText@@footnote 1@R. Y. Jou et al., Designs, Analyses, and Tests of A Spiral-Grooved Turbo Booster Pump, J. Vac. Sci. Technol., A, 18(3), 1016 (2000). @footnote 2@H. P. Cheng, R. Y. Jou, et al., Inner Pressure Measurement of Turbo Molecular Pump, J. Vac. Sci. Technol., A18(4), 1766 (2000).