The invention discloses a method for recycling nitrogen gas and sulfur dioxide from calcining iron pyrite burner gas through variable-voltage variable-frequency adsorption. The method comprises the following steps: dedusting, purifying, drying and cooling the calcining iron pyrite burner gas, and removing dust particles and rust by a refining sulfuric acid burner gas filter made of a 200-mesh polytetrafluoroethylene material; deeply dehydrating by a refining dehydrating tank in a refining manner, deoxidizing and removing carbon dioxide, separating N2 and SO2 through variable-voltage variable-frequency adsorption, compressing or cooling and performing gas-liquid separation to obtain liquid SO2, bottling the separated nitrogen gas and the liquid SO2 for industrial use, and enabling SO2 which is not liquefied and separated to enter a circulating process of compression or cooling and gas-liquid separation, so as to enable SO2 to be separated continuously. The method realizes comprehensive utilization and zero emission of mixed burner gas containing a great amount of nitrogen gas and sulfur dioxide caused by calcining of iron pyrite, the obtained liquid SO2 has high purity, the process is green, safe and energy-saving, and realizes zero emission and low cost.