The invention discloses a steel structure and a concrete column connection structure. The steel structure comprises a fixing plate, a through opening is formed in the fixing plate, a screw rod is rotatably connected in the through opening, a first gear fixedly sleeves the screw rod, a second gear meshed with the first gear is disposed in the through opening, the inner walls of the second gear andthe through opening are rotatably connected by a rotating rod, the end, away from the second gear, of the rotating rod penetrates through the inner wall of the through opening and is fixedly connectedwith a handle, a clamping bar is slidably inserted into one end of the handle, a plurality of clamping slots corresponding to the clamping bar are formed surrounding the outer wall of a fixing plate, the end, near the fixing plate, of the clamping bar is fixedly sleeved with a cutting ferrule, the end, away from the cutting ferrule, of the clamping bar is fixedly connected with a clamping block,and the screw rod is threadedly sleeved with two pressing plates. The steel structure makes a steel component can be well fixed with a concrete by the arrangement of the adjustable pressing plates, thereby ensuring that the structural strength of a structural member is improved.