In view of the defects brought by the single power form of traditional electric vehicle,the working principle of electro-mechanical-hydraulic power-coupled electric vehicle was proposed,in which electromechanical-hydraulic coupling was used to realize the arbitrary mutual transformation of electrical energy,mechanical energy and hydraulic energy,overcoming many disadvantages of traditional electric vehicles.The five basic modes of the power transmission of electro-mechanical-hydraulic power-coupled electric vehicles were described.A mathematical model of the mechanical,electrical and hydraulic power matching of the electro-mechanical-hydraulic power coupled electric vehicle was established.Based on the CLTC operating conditions,AMESim and Simulink were used to jointly simulate the characteristics parameters of the electro-mechanical-hydraulic power coupled electric vehicle such as following,electric power,energy storage pressure and power consumption.The feasibility of the electro-mechanical-hydraulic power coupled electric vehicle power transmission principle is verified.