The invention discloses a method for oxidizing cyclohexane to prepare hexane diacid through a one-step method, which comprises the following steps: a, mixing the cyclohexane with a phase transfer catalyst, adequately agitating the mixture, adding an oxidant to the mixture, and reacting the mixture for 4-12 h under the conditions that a temperature is 140-180 DEG C and a pressure is 0.5-2.5 MPa to obtain a reaction product mixture, wherein the phase transfer catalyst is [(C18H37)2n(CH3)2]11[WZnRu2(OH)(H2o)(ZnW9O34)2], [(C16H37)N(CH3)3]6Na6[WZnPt2(OH)(H2O)(ZnW9O34)2], or [(C16H33)N(CH3)3]12[WZn2Ru(OH)(H2O)(ZnW9O34)21]; and b, after the reaction product mixture is cooled to a room temperature, filtering and washing the reaction product mixture to obtain a solid, and drying the solid to obtain the hexane diacid. The invention further provides a catalyst for oxidizing the cyclohexane to prepare the hexane diacid; the catalyst has extremely strong catalytic activity and selectivity; in the method provided by the invention, not only is the cyclohexane a reactant, but also the cyclohexane is a solvent; air or oxygen is used as the oxidant; other side products are not generated; and the pollution to the environment is avoided.