Abstract: Due to its unique advantages of large storage scale and without limitation by geographical conditions, liquefied air energy storage（LAES） can participate in peak-regulation transformation of existing coal-fired power units to promote the construction and development of new power systems. Therefore, a novel LAES system coupled with coal-fired power unit was proposed, and the thermodynamic and economic models of the coupling system were established to analyze the influence of the change of energy storage capacity on the coupling system. Results show that a 44.2 MW/176.8 MW·h LAES system can be selected for comprehensive considerations when coupling with a 670 MW coal-fired unit.Considering three low-load（30%THA, 40%THA, and 50%THA） conditions for the coal-fired power unit, the round-trip efficiency of the coupling liquefied air energy storage system is about 51%, which is about 9 percentage points higher than that of the independent LAES system. The rate of return on investment of the coupling LAES system is close to 10%, and the investment can be recovered within 14 years. The sensitivity analysis results show that it is beneficial to improve the economic performance of the system through enlarging the difference between peak and valley electricity prices.