In order to improve the power system's ability to accept renewable energy output, reduce the equivalent load volatility of the regional power grid, maintain system security and enhance the response enthusiasm of the owners of Electric Vehicle(EV), taking the minimum load fluctuation in the grid power system, and the optimal economic benefits of the EV owners as the optimization goals, a collaborative scheduling model of large-scale EVs and renewable energy is established to reasonably arrange the charging and discharging behaviors of EVs. The maximum fuzzy satisfaction method is adopted to turn the multi-objective problem into a single objective problem. At the same time, an Improved Firework Algorithm(IFWA) is proposed. The algorithm performance is improved by optimizing the initial population distribution and a double elite-tournament selection strategy. Finally, by comparing the results of the calculation examples, it is verified that the coordinated scheduling of large-scale EVs and renewable energy can effectively suppress the fluctuation of equivalent load and create benefits for EV users. The improved algorithm reduces the computational overhead with a higher accuracy.