The invention relates to a method for anaerobically degrading feather keratin with a microbial strain 18D-TA, belonging to the technical field of microorganisms. The method comprises the following specific steps of: A, treating feathers: cleaning feathers with water, putting into a drying oven of which the temperature is 45-55 DEG C, and drying for 2-3 days for later use; and B, inoculating the strain: performing high-temperature moist-heat sterilization on a culture medium and the feathers treated in the step A, inoculating the strain 18D-TA in the amount of 2-10 percent, and anaerobically standing and culturing at the temperature of 45-60 DEG C for 8-10 hours till feather down falls off, wherein the feathers are completely separated from feather stems 18-24 hours later, and the feather stems are degraded in different degrees. Compared with other aerobic bacteria, the strain used in the method has the advantages: more products can be accumulated, so that ventilation equipment is not required to be provided, and the energy consumption is lowered greatly; and meanwhile, the efficiency is high, the fermenting period is short, racemization of most amino acids is avoided, and the absorption applicability of a feather hydrolysis product is enhanced.