The invention discloses a GIS room equipment in-out dustproof transition room which comprises a transition room body, galvanized square tubes, ceiling supporting rods, a dust removal purifier and universal wheels, the galvanized square tubes are distributed in the transition room body, and transverse tubes are arranged at the tops and the bottoms of the transition room body and the galvanized square tubes. The top of the transverse pipe is connected with a ceiling supporting rod through a sliding rail, the top and the bottom of the ceiling supporting rod are both connected with movable shafts, universal wheels are arranged at the two ends of the bottom of the transverse pipe, and dust removal purifiers are distributed on the front side and the rear side of the two ends of the transition room body. According to the GIS indoor equipment dust-proof transition device, the air cleanliness during installation of GIS indoor equipment is guaranteed, the installation efficiency is improved, losses caused by construction period delay and the like are reduced, the installation quality and the installation progress are effectively improved, practicability is high, installation is easy and convenient, and the GIS indoor equipment dust-proof transition device is suitable for popularization and application. The method can be used in various construction projects subsequently.