Connecting device at joint of steel structures

The utility model discloses a connecting device at the joint of steel structures, which comprises a first steel structure and a second steel structure, a clamping block is integrally formed on one side of the first steel structure, a buckle is integrally formed on one side of the second steel structure, the buckle is connected with the clamping block in a clamping manner, and protective pads are placed on two sides of the buckle and the clamping block. Connecting frames, clamping blocks and buckles are placed on the two sides of the protective pad, a plurality of threaded holes are formed in one side of the protective pad and one side of the connecting frames, fixing cylinders are movably connected to one sides of the threaded holes, first threaded rods are movably connected to one sides of the fixing cylinders, clamping grooves are formed in the inner walls of the two sides of the connecting frames, and clamping strips are movably connected to one sides of the clamping grooves; a supporting frame is integral