The invention discloses a power-free aerobic biological treatment method for rural domestic sewage, belongs to sewage treatment (C02F), and mainly aims to solve the problems of large civil engineering quantity, high investment cost, huge aerobic aeration energy consumption and the like existing in the conventional domestic sewage treatment process. According to the technology, a power-free aerobic air channel comprehensive treatment system is invented by using the advantage of rich mosses and bamboo for weaving in rural areas. The method comprises the following steps: introducing sewage into a water distribution groove through a water inlet branch tube valve, and uniformly distributing the sewage at the bottom of the water distribution groove to complete primary natural aeration; introducing the sewage into an upper layer moss filling area, a middle layer moss filling area and a lower layer moss filling area of a bamboo basket in the water distribution groove in a drip irritation way, performing automatic oxygen aeration by using the power-free aerobic air channel comprehensive treatment system to complete secondary natural aeration, and gradually purifying the sewage under the actions of filtration, adsorption, degradation and the like of the mosses and microorganisms. The system has the advantages of no need of manual aeration, no power consumption, no need of building complex buildings, small engineering quantity, no equipment investment, easiness and convenience in operation and capability of realizing unmanned operation, and is suitable for treatment of medium and low-concentration domestic sewage in rural areas.