Abstract: To achieve the thermal-electric decoupling, a method of integrating a combined heat and power (CHP) unit with compressed air energy storage (CAES) was proposed. A thermodynamic model of a 300 MW CHP unit was developed based on Ebsilon software to analyze the variations in the unit's heat-power feasible region, energy utilization efficiency, and exergy efficiency. Additionally, a particle swarm optimization (PSO) algorithm based on position constraints was adopted to optimize the system's operation strategy with the objective of minimizing overall coal consumption. Results show that coupling with CAES can significantly expand the heat-power feasible region and enhance the deep peak shaving capability of the unit, providing a maximum increase of 35.0 MW in deep peak shaving power. When the boiler output and the power of the CAES module are fixed, the lower the heating load of the unit, the more significant the change in its energy utilization rate. Both the energy utilization efficiency and exergy efficiency of the unit are negatively correlated with charging power and positively correlated with discharging power. Within a typical daily cycle, the adjustment of charging and discharging power can increase the unit's energy utilization efficiency by up to 2.54% and the exergy efficiency by 1.41%. Furthermore, the unit can save 52.5 t/d of standard coal and reduce CO₂ emissions by 136.5 t/d.