The invention discloses a method for pre-burying drilling tool oblique hole directional opening, and relates to the field of drilling. The method includes the following steps that step 1, the positionand orientation of an oblique hole are determined; step 2, a drilling rig base basal groove is excavated; step 3, pouring is performed on the drilling rig base basal groove and setting is performed for 24 hours and then a drilling rig is installed; step 4, an opening drilling tool is connected to a driving drill pipe; the opening drilling tool is removed, and a drilling tool base basal groove isexcavated at the position of the hole opening of the oblique hole; step 5, the drilling rig is moved to the position of the oblique hole, the opening drilling tool is installed and tightened; the driving drill pipe is lowered, the opening drilling tool is placed into the drilling tool base basal groove, and then a lower chuck of the driving drill pipe is tightened; step 6, a layer of insulation film wraps the opening drilling tool; step 7, concrete is poured in the drilling tool base basal groove; and step 8, after the concrete is finally set for 24 hours, opening and drilling are performed. The method of directly pre-burying the drilling tool is adopted, the shortcoming that a pre-buried guiding pipe is prone to causing inclination and orientation to be skewed is overcome, and the hole forming quality of the oblique hole opening stage is ensured.