The energy storage capacity of electric vehicles (EVs) enables them to have the potential to form an uninterruptible power system (UPS) when the power supply is interrupted in the community. To solve the problems related to the reasonable power distribution and accurate voltage tracking control for EVs accessed community UPS, an integrated cooperative control strategy based on the multi-agent system is proposed in this paper. First, an improved power distribution strategy based on the $P$-$f$ droop control is developed to realize the state-of-charge balancing of EVs having different capacities and voltages. Then, a cooperative voltage tracking control strategy for EV energy storage units is developed to realize the accurate voltage tracking control, and a second-order sliding mode differentiator is designed to estimate the derivative of the virtual control law. Besides, the unknown part of the model is approximated by the fuzzy logic system, and the neighborhood synchronization error is upper-bounded by the prescribed performance control. The integrated cooperative control strategy designed is completely distributed. Results show the effectiveness of the proposed integrated cooperative control strategy.