The invention discloses an auxiliary drilling device for installing a building monitoring mark. The auxiliary drilling device structurally comprises an impact drill column head, a shaft rod rotating seat, a axial-rotating dust-proof barrel, a gun barrel groove shell, a Y-shaped clamping buckle frame, a motor transmission box, a trigger holding handle frame, a key lock hole disc, a micro stepping motor and an auxiliary handle rod, wherein the axial-rotating dust-proof barrel is nested at the left end of the gun barrel groove shell, and the impact drill column head is inserted into the left sideof the shaft rod rotating seat. According to the auxiliary drilling device, the axial-rotating dustproof barrel is provided with a motor shaft moving device, a double-push-rod piston cylinder, a fluted disc traction mechanism, a roller transmission mechanism, a shaft rod rotating device and a spring telescopic device, a ratchet wheel rotating mechanism and an impact shaft rod supporting seat, sothat the functional performance of forward and reverse rotating of the drilling device is high, the drilling intensity is increased through forward rotating, the dust and the gravel are sucked in thereverse rotation manner through reverse rotating, the air pollution is avoided, the cost is also saved, the engineering progress is improved, the integrated synchronous multifunctional effect is achieved, meanwhile, forward and reverse rotating isolation does not interfere with the drilling action, so that the building monitoring mark is more convenient to install.