In this paper, a novel electro-mechanical transmission system using dual-rotor motor which is suitable for urban public transport is designed, and the working principle of the transmission system is expounded combining with the characteristics of the dual-rotor motor. Theoretical analyses and simulation of speed, torque and power flow of the transmission are conducted. According to the simulation results, the inner motor of the dual-rotor motor adopts the speed regulation, which is used for optimizing the working point of the internal combustion engine; the outer motor of the dual-rotor motor adopts the torque regulation, which is used for adapting the change of load torque. Based on the drive cycle, the rated torque and rated speed of dual-rotor motor are matched considering the economy and dynamic performance. According to the dynamic characteristic graph, the matching results meet the dynamic performance of the urban public transport.