The invention discloses a method for preparing KA oil through cyclohexane oxidation. The method comprises the steps of synthesizing cyclohexane oxidation reaction liquid, decomposing cyclohexyl hydroperoxide, and carrying out rectification to obtain the AK oil, and is characterized in that before the cyclohexyl hydroperoxide decomposition step, the cyclohexane oxidation reaction liquid is treated through the following steps: (1) hydrolysis reaction: continuously introducing water and cyclohexane oxidation reaction liquid into a hydrolysis reactor for reaction, so as to obtain the reaction liquid; (2) liquid-liquid layering: layering the reaction liquid into an upper layer as an oil phase and a lower layer as a water phase, and collecting the upper oil phase, so as to obtain the treated cyclohexane oxidation reaction liquid rich in cyclohexane, cyclohexyl hydroperoxide, cyclohexanol and cyclohexanone. According to the method, the follow-up saponification alkali liquor dosage and waste alkali liquor discharge amount can be greatly decreased, the concentrations of cyclohexyl hydroperoxide in the oxidation reaction liquid and various intermediate products are remarkably decreased, the yield of AK oil is increased, mixed dibasic acid with a high added value is produced, and the method has the advantages of being simple in process, high in yield, good in economic benefits and capable of greatly reducing waste water and waste residue emission.