Emergency power vehicles are crucial in ensuring power supply continuity when power failure happens. However, power quality issues on the load side also seriously affect the safety of emergency power supply. Therefore, this paper designs a comprehensive power quality management device suitable for emergency power supply vehicles. It combines power electronic devices and batteries to solve the problem of diesel generators’ slow transfer speed and susceptibility to imbalanced and impulse-type loads. This device can supply stable voltage and frequency before the diesel generator starts up. After that, it can achieve the goal of compensating three-phase unbalance and power fluctuation, providing comprehensive power quality management for emergency power supply. It also achieves smooth transitions between different operating states, significantly protecting the safe operation of diesel generators. This proposal was verified through simulations using Matlab/Simulink software, achieving ideal results.