The optimal allocation of independent microgrid capacity is an important link in the planning and construction of microgrid.This paper presents a new quantum inspired gravitational search algorithm based on levy flight for independent microgrid systems including wind power generation, photovoltaic power generation and battery.On the basis of ensuring the reliability of power supply and the consumption of new energy, a model for optimizing the capacity of independent microgrid was established.The global optimization ability of the quantum gravity search algorithm was enhanced by introducing the dynamic adjustment strategy of contraction and expansion coefficient and levy flight.The model proposed in this paper is used for simulation analysis, and compared with the results of other gravitation search algorithms and particle swarm optimization algorithms, the results show that the proposed algorithm has high solution accuracy and stability, and can ensure the economic and reliable operation of the independent microgrid system.