The invention relates to a double-air-chamber automatically inflatable life jacket. The double-air-chamber automatically inflatable life jacket comprises double-layer air chambers which do not communicate mutually, wherein a head hole through which the double-air-chamber automatically inflatable life jacket sleeves the head of a person is formed in the double-layer air chambers; one or more air exhausting and blowing valves and one or more CO2 air cylinders are fixed on each layer of the double-layer air chambers, and the CO2 air cylinders are controlled by one or more air cylinder valves; a plurality of reflective tapes are fixed on a layer, which is not close to human bodies, of the double-layer air chambers, and a belt through which the whole life jacket is fixed on the human bodies is fixed on a layer, which is close to the human bodies, of the double-layer air chambers. When the double-air-chamber automatically inflatable life jacket is made, the space allowing the CO2 air cylinders to be mounted is reserved in the double-layer air chambers, the CO2 air cylinders are mounted in the double-layer air chambers, and the air cylinder valves of the CO2 air cylinders are exposed outside the double-air-chamber automatically inflatable life jacket. The air exhausting and blowing valves which are convenient for people to blow air and exhaust air are mounted outside the double-layer air chambers. According to the double-air-chamber automatically inflatable life jacket disclosed by the invention, under the condition that one air chamber is in air leakage, the same effect can be achieved through the other air chamber.