The invention discloses a drilling hole-forming process of a rock-socketed pile. The drilling hole-forming process includes the following steps that under the guiding action of a steel sleeve and first guiders, a portion, with the steel sleeve, of the rock-socketed pile is drilled to form a hole through a first drill bit; under the combined guiding action of a second guider and the first guiders, the rock-socketed section without the steel sleeve is drilled to form a guiding hole through a second drill bit; and after drilling of the guiding hole is finished, the second guider is dismantled, the second drill bit is replaced with a third drill bit, a third guider is mounted at the front end of the third drill bit, under the combined guiding action of the third guider and the first guiders, drilling of a final formed hole is performed, and the third guider is always located in the guiding hole in the drilling process. By means of the drilling hole-forming process of the rock-socketed pile, the effect that the slopes of the drill bits are kept consistent with the slope of the steel sleeve during construction of an oblique rock-socketed pile can be well guaranteed, the hole-forming quality is improved, the hole walls are smooth, intact and high in straightness, the construction requirements are met, and the construction efficiency is improved. The drilling hole-forming process of the rock-socketed pile is easy to implement, low in construction cost and good in economic benefits.