A virtual power plant takes advantage of interactive communication and energy management systems to optimize and coordinate the dispatch of distributed generation, interruptible loads, energy storage systems and battery switch stations, so as to integrate them as an entity to exchange energy with the power market. The optimal dispatch strategy of a virtual power plant, based on a unified electricity market combining day-ahead trading with real-time trading. The operation models of interruptible loads, energy storage systems and battery switch stations are specifically described in this proposed work. The virtual power plant applies an optimal dispatch strategy to earn the maximal expected profit under some fluctuating parameters, including market price, retail price and load demand. The problem of optimal power flow with linear programming model will be carried out in a week to maximize virtual power plant profits. Uncertainty due to the nature of solar and wind power with pumped storage power plant to take advantage of a more flexible generation process as well as a traditional power plant as a backup, will be eliminated. Efficiency of model is analyzed and presented, using a real sample. Simulation tests are performed on a 10-machine system using Matlab software.