The invention discloses a quick connecting device for steel bars comprising a fixed valve body and a moving valve body. The quick connecting device for the steel bars is characterized in that the fixed valve body is connected to an end cover with a round hole in a threaded mode to fix the steel bars, the inside of the fixed valve body is provided with a limited block for limiting the outside surface of the steel bar end, and bar-shaped holes are formed above and below one end, close to the end cover, of the fixed valve body; first protrusion bodies are arranged in the bar-shaped holes, a groove-built-in spring is disposed between the upper and lower first protrusion bodies for supporting, and a telescopic rod is arranged in the spring; a connecting body is arranged in the fixed valve bodyand the connecting body is fixedly connected to the fixed valve body in a threaded mode, one of the steel bars is squeezed and fixed between the connecting body and the moving valve body, and holes connected through pins are up-down formed in the corresponding positions on the pressing surface of the moving valve body and the fixed valve body; and the connecting body is sleeved with a rubber ring,the interior of one side, close to the moving valve body, of the connecting body is hollow, and an inner plug is arranged in one side, close to the steel bars, of the connecting body and is connectedwith the connecting body in a threaded mode. The quick connecting device for the steel bars is stable in structure and convenient to popularize, and the connection of the steel bars is simpler and more convenient through the arrangement of the spring in a connecting sleeve.