The invention discloses a thick oil air injection relaxation catalytic oxidation emulsion catalyst and a preparation method thereof. The catalyst is composed of the components of, by mass: 5-15 parts of N-lauroyl ethylenediamine transition metal triacetate, 30-40 parts of kerosene, 40-60 parts of water, and 5-10 parts of an emulsifier. The air injection relaxation oxidation catalyst prepared by the invention has characteristics of both an emulsification viscosity reducer and an oil-soluble catalyst. The catalyst provided by the invention can be used in thermal recovery. In a post stage of thermal recovery, the catalyst is stirred with water, such that an emulsion is produced; the emulsion is injected into a reservoir; with the oil solubility of the catalyst, the catalyst in the reservoir is sufficiently mixed with thick oil; and air is injected into the reservoir, such that relaxation catalytic oxidation occurs.