The working principle of multi-mode mechanical-electronic transmission machinery was introduced. The broken line speed characteristics of dual-mode mechanical-electronic transmission were proposed, and a design method based on the speed characteristics of dual-mode mechanical-electronic transmission was provided. Four kinds of dual-mode mechanical-electronic transmission schemes were designed. Theoretical analysis and simulation on speed, torque and power characteristics were compared. The program of the engine input connecting with the gear ring of the first planetary gear set met the vehicle requirements of the relationship between speed, torque and power. The parameter adjusting range of planetary gear set was wider, program application was flexible. The relative electric power split, the motor weak magnetic ratio, the cooling method and system application background must be regarded as the considering factors.