The invention relates to the technical field of copper smelting, and particularly discloses a treatment system for low concentration SO2 flue gas of an anode furnace. The treatment system comprises the anode furnace, a smelting furnace and a converting furnace. An exhaust gas outlet of the anode furnace, an exhaust gas outlet of the smelting furnace and an exhaust gas outlet of the converting furnace are connected with a first gas inlet, a second gas inlet and a third gas inlet of a gas mixing chamber through pipelines respectively, and a gas outlet of the gas mixing chamber is communicated with a flue gas acid-making system. On the basis that an existing flue gas acid-making system is matched for copper smelting, the low concentration SO2 flue gas in the anode furnace and high concentration SO2 flue gas in the smelting furnace and the converting furnace are communicated with the inside of the gas mixing chamber through pipelines respectively, a flue gas mixture obtained by mixing multi-source flue gas can meet the requirement of the flue gas acid-making system for the SO2 concentration, and therefore the low concentration SO2 flue gas can be effectively recycled.