The invention relates to the field of guaiacol transformation and utilization and in particular to an application of a nickel-based catalyst as a catalyst for preparing phenol and cyclohexanol from guaiacol. A preparation method of the nickel-based catalyst comprises the following steps: heating a supported NiO catalyst to 200-500 DEG C according to a heating velocity procedure of 5-20DEG C/minute, and carrying out reduction so as to prepare a supported NiOx catalyst with low-valent nickel, wherein x is not greater than 1. At 200-500 DEG C, the supported NiO catalyst is reduced into a low-valent supported NiOx catalyst, therefore, the supported NiOx catalyst can be applied to transformation of guaiacol, two products of phenol and cyclohexanol can be prepared, and the application of the nickel-based catalyst can be expanded.