The invention relates to an alloy catalyst and a preparation method and application of catalyst. The alloy catalyst is shown as the formula I, namely TM(100-x)-REX. The alloy catalyst can be used for carrying out catalytic oxidation on cyclohexane to directly generate adipic acid, glutaric acid, succinic acid and KA oil in the presence of oxidizing agents such as air, oxygen gas or oxygen-enriched air, and the main product is adipic acid; the appropriate reaction conditions are as follows: the temperature is 130-150 DEG C and the pressure is 1.0-3.0MPa. The alloy catalyst has the characteristics of good activity, long service life, easiness in separation and the like; the metal alloy catalyst is characterized by being used for carrying out catalytic oxidation on cyclohexane to generate adipic acid, glutaric acid and succinic acid in the presence of air by one step, the reaction process is green and has an energy-saving effect, and the greenhouse gas emission can be reduced.