Vacuum pump plays an important role in vacuum applications. The rotor and stator profile is one of the key factors for improving pump performance. In this paper, the traditional trochoidal vacuum pump that the rotor and stator profile both are trochoidal equation was introduced. The profile of trochoidal vacuum pump with two angle rotor was studied. In order to simply the design and manufacture, the rotor profile was substituted by the arc curve. The design parameter and performance was deducted on slenderness ratio. The slenderness ratio should larger than 4, otherwise the down part of the stator profile would be dent to upper. When slenderness ratio is 4, the utilization ratio of volume would be getting the maximum value, 0.5851942. The utilization ratio of volume was decreased with the slenderness ratio increased.