The invention discloses a building steel plate fixing device. The building steel plate fixing device comprises a fixing base; the four corners of the fixing base are all fixedly connected with fixingcolumns, and the tops of the fixing columns are fixedly connected with supporting rods; the top of the fixing base is fixedly connected with four supporting blocks, and the supporting blocks are provided with slide grooves; and slide blocks are slidably connected into the slide grooves, and the positions, located on the upper surfaces of the supporting blocks, of the tops of the slide blocks are fixedly connected with extrusion plates. A using method of the building steel plate fixing device comprises the steps of S1, preparation before using, S2, size adjustment, and S3, fixing. Compared withthe prior art, through mutual action of screws, the supporting blocks, the extrusion plates, buffer blocks, buffer springs and buffer rods, building steel plates with different sizes can be fixed through convenient adjustment, accordingly, fixing is more convenient and quicker, different fixing devices do not need to be replaced, and application is wider.