The present invention provides a method for calculating a destruction rate of refrigerant by establishing a calibration line using standard refrigerant gases and measuring the amount of refrigerant remaining in exhaust gas discharged after destruction of waste refrigerant. For this purpose, the present invention provides a method for calculating a destruction rate of refrigerant, the method including: establishing a calibration line using standard refrigerant gas samples whose concentrations are known; sampling exhaust gas finally discharged after decomposition of waste refrigerant; measuring the concentration of refrigerant remaining in the sampled exhaust gas; and calculating the amount of undestroyed refrigerant using the concentration of refrigerant remaining in the exhaust gas, the amount of exhaust gas discharged, and the known density of refrigerant.