Nuclear plants are facing more and more peaking pressure, and combined operation with compressed air energy storage (CAES) systems is an effective approach to improve its peaking capacity. This work first simulates and conducts the exergy analysis for the CAES system. The results show that exergy efficiency of the CAES system is about 51.7%, as well as the exergy loss are primary in the fuel combustion and compressed air cooling processes, accounted for 25.4% and 11.3% of total exergy, respectively. Subsequently, three combined operation modes between CAES system and nuclear power plants for power grid peaking are investigated, which shows that three section tracking mode and incomplete tracking mode can achieve the balance between peaking effects and peaking cost.