The present invention discloses an anti-floating anchor dual-drill hole-forming construction method. The method concretely comprises the following steps of: the step 1: excavation of a construction working surface and location of hole sites; the step 2: drill machine in place and installation of an outer sleeve drilling tool; the step 3: drilling of an outer drill to form a hole; the step 4: drilling of an inner drill to form a hole; the step 5: hole cleaning and pull-out of the inner drill; the step 6: putting an anchor rod; the step 7: primary ordinary pressure grouting; and the step 8: secondary high pressure splitting grouting. The anti-floating anchor dual-drill hole-forming construction method employs the outer drill whole sleeve to be drilled into a retaining wall, employs the outersleeve to enter a rockface, provides the total sleeve retaining wall in the drilling process of the inner drill to ensure the stability of an unconsolidated formation and rapidly form holes with highquality, and therefore, the anti-floating anchor dual-drill hole-forming construction method is simple to operate, safe, controllable, low in integration construction cost, saved in energy and environmentally friendly, and is suitable for anti-floating anchor dual-drill hole-forming construction of the fragile formation.