The invention relates to a method for controlling trepanning verticality of an upside-down vertical hole. The method comprises the steps that a base is mounted, a base groove is excavated, the verticality is adjusted, a drilling rig is reinforced, a drilling tool is pre-buried, drilling starts, the drilling rig is started for starting drilling after concrete is solidified, and trepanning work of the upside-down vertical hole is completed. According to the technical scheme, the trepanning drilling rig is pre-buried at the drilling hole position, then the trepanning work is conducted, the requirements for the verticality at the upside-down vertical hole construction trepanning stage can be effectively met, thus the hole forming quality at the upside-down vertical hole trepanning stage is greatly improved, the national standard requirements for the upside-down vertical hole are met, the time of the upside-down vertical hole construction trepanning stage is saved, late-stage deviation correction work and even a waste hole accident caused by the fact that the verticality does not meet the standard at the trepanning stage are avoided, and in the actual production process, the method hasquite high application and popularization value.