Single screw pump is a kind of inside engaged biased rotation volume pump, which is widely applied in a number of major fields of the national economy. The key components are the rotor and the stator with complex spiral surface, which are meshing with each other. The machining accuracy of them makes effect on the working performance of single screw pump directly. In this paper, the operation principle of the single screw pump with large lead and multiple heads was represented, and the mathematical model of the rotor and the stator was established. The three-dimensional models of rotor and stator of single screw pump were put into effect with three-dimensional modeling software UG. This study has laid a theoretical foundation to the research of new manufacturing technology of the spiral curved surface and the development of the corresponding machine.