Abstract: To improve the performance of an advanced adiabatic compressed air energy storage (AA-CAES) system, a solar auxiliary heating subsystem was coupled to the original system, and subsequently, a study was conducted on the performance of the newly coupled system. Results show that at a fixed number of compressor stages, the temperature of cold and hot tanks increases slowly with the rising number of turbine stages, while at a fixed number of turbine stages, the temperature of cold and hot tanks decreases with the rising number of compressor stages. When the number of compressor stages is equal to that of turbine stages, the energy storage efficiency, the energy storage density and the coupled energy storage efficiency of the system would be higher than the case the two numbers are not equal. With the enhancement of heat exchanger effectiveness, the temperature of cold and hot tanks, the expansion work and the compression work increase, while the energy storage efficiency and the coupled energy storage efficiency of the system increase first and then decrease.