As a modern power grid that integrates advanced communication technology, sensor measurement technology, and intelligent control technology, the smart grid has good economy, reliability, and stability. Building a strong smart grid has important strategic significance for developing the national economy and improving Comprehensive National Power. The balance of electricity supply and demand, as a physical feature of the power system, determines the energy matching relationship between generation and consumption. Unreasonable power generation may lead to unmet electricity demand, as well as excess electricity and waste of resources. The energy storage has solved the problem of imbalance between supply and demand in most environments. The energy storage equipment provides a buffer space for electric energy, effectively adjusts the time unevenness of power grid load, realizes peak shaving and valley filling, and reduces the operation cost of the power grid. Taking the aboveground energy storage power station as the research object, the 3-D unsteady model of the small and medium-sized compressed energy storage system was established by using the FLUENT simulation software, and the correctness was verified through experimental methods. The influence of different environmental temperatures, chamber inflation flow rate, the thermodynamic characteristics of the surface condition and working chamber of the and energy storage were studied. The results show that the environmental temperature and expansion flow of oil storage chamber have important effects on its thermodynamic characteristics, while the surface conditions of oil storage chamber wall have little effect on its thermodynamic characteristics.