In this paper, we model 48V MHEV with P0 + P4 structure and develop HCU control algorithm. This study analyzes the characteristics of fuel consumption and regenerative braking according to the ratio of two motor powers. The HCU control algorithm consists of a mode decision algorithm and a power distribution algorithm. The vehicle model was developed using the Autonomy program. The HCU control algorithm was developed using Matlab/Simulink. Fuel economy simulation and regenerative braking energy analysis are performed in the FTP75 driving cycle environment. In this paper, the operating characteristics of 48V MHEV are compared according to the power ratio of two motors, and the regenerative braking energy is analyzed.