The traditional vacuum booster is gradually replaced by Brake-by-Wire system (BBW) in modern passenger car, especially Electric Vehicle (EV). Some mechanical and hydraulic components are replaced by electronic components in Brake-by-Wire system. Using BBW system in modern passenger vehicles can not only improve the automotive safety performance, reliability and stability, but also promote vehicle maneuverability, comfort, fuel economy and environmental protection. Although vehicle's braking performance is greatly improved by using BBW, the system will inevitably consume some energy of the vehicle power supply, thus introducing unexpected drawback in comparison with the traditional vacuum assist braking system, since it doesn't need any electric power. Therefore, the analysis of energy consumption on typical main cylinder booster based BBW system under typical driving cycles will contribute to advanced design of current advanced braking system.In this paper, energy consumption of the typical main cylinder booster based BBW system is simulated by changing the brake response time and reduction ratio of the system under different driving cycles. The average power needed of conventional BBW system is also calculated. Energy consumption of the conventional and typical main cylinder booster based BBW systems is compared. The results show that the energy consumption of the typical main cylinder booster based BBW system is around 30W∼60W which is obvious better than the conventional BBW system with power need of 500W under typical driving cycles, such as USDC, EDC and JDC. The energy consumption of the Brake-by-Wire system can be reduced obviously through an optimal design on parameters of the system's actuator.