Dual-rotor Piston Engine (DRPE) is a new type of differential rotary engine. Compared with traditional engines, DRPE has many advantages. The complex valve systems can be omitted. Its structure is more compact. Its power density is higher, and so forth. In the paper, we analyze the working characteristics of DRPE, and figure out the mechanical structure characteristics of the Differential Velocity Drive Mechanism (DVDM) of the DRPE. Define its kinetic parameters. Then establish the mathematical models for the kineto-static analysis of the DVDM by using vector mechanics methods. The mathematical models were calculated by Matlab. The mechanical characteristics of DRPE’s main components were obtained. In order to verify the rationality of the established mathematical models, multi-body dynamics simulations were done. The virtual prototype model of the DRPE-350 was established in the RecurDyn. The simulation results compared with the calculation results, the value changing rules are almost the same. The changing processes are all four cycles. Impact positions are basically the same. It shows that the established dynamic theory model conforms to the actual situation. It is reasonable and can be trusted. It can be used as the theoretical foundation for the follow-up improvements of the DRPE.