With the global energy structure adjustment and the transformation of the automotive industry towards electrification, the braking system of new energy vehicles needs to balance energy recovery and driving safety. The traditional vacuum-assisted hydraulic braking system is no longer able to meet the requirements of new energy vehicles for energy recovery rate and precise regulation of braking force. The mechanical-hydraulic composite braking system has emerged. This system integrates the advantages of hydraulic braking and motor regenerative braking, retains the reliability of mechanical braking, and has become a core technology of new energy vehicles. Through joint simulation with Simulink, AMESim, and CarSim and real vehicle tests, this paper studies the hierarchical coordinated control strategy of electro-hydraulic composite braking system; elaborates on the architecture and key technologies of the mechanicalhydraulic composite braking system, analyzes its compatibility in new energy vehicles, discusses technical pain points and optimization strategies, and analyzes the impact of relevant regulatory environment and standardization, providing a reference for the engineering application of this technology.