The invention discloses a method for preparing a zinc-air battery catalyst of a carbon-nitrogen-based iron material. The method comprises a step of obtaining a polypyrrole-iron complex by synthesis, astep of obtaining a bimetallic zeolite imidazole framework nanocrystal by synthesis, a step of obtaining a composite material formed by the synthesizing the bimetallic zeolite imidazole framework nanocrystal and a carbon-nitrogen-based iron material framework, and a step of dissolving a composite material as a catalyst and acetylene black in a solution containing ethanol and Nafion, performing ultrasonic processing to obtain a uniformly dispersed slurry, and uniformly applying the slurry to fiber paper processed by polytetrafluoroethylene to be a positive electrode of a zinc-air battery. Thecatalyst proposed by the invention has excellent ORR performance and excellent OER catalytic activity, the performance of the catalyst is better than the performance of a commercial Pt/C catalyst andis better than that of a bifunctional catalyst in the prior art.