The invention discloses a recycling method of protective atmosphere in an annealing furnace. The method is characterized in that the recycling method comprises the following steps: (1) the protective atmosphere is extracted from a protective atmosphere extraction outlet in the furnace; (2) the extracted protective atmosphere is cooled until the temperature is lower than 20 DEG C, and the protective atmosphere is processed through dehydration treatment; (3) after being cooled, the pressure of the protective atmosphere is risen to more than 30KPa through a blower, and then is delivered to a storage tank for storing; before being delivered into the storage tank, the content of H2 in the protective atmosphere is measured on a protective atmosphere recovering pipeline, and the calorific value thereof is calculated; if the calorific value is in the designed calorific value range, the protective atmosphere is used by a burning pipeline system directly to heat a band steel; if the calorific value is not in the designed calorific value range, natural gas starts up and is pumped in the pipeline system, the natural gas is replenished, and then the protective atmosphere is supplied to a burning system for using after the calorific value is adjusted to the designed calorific value range. The recycling method is utilized to recover the protective atmosphere in the annealing furnace, so that the energy is saved and the manufacturing cost is lowered; in addition, the recycling method is easy to operate, and the application range is wide.