Point-making distance-marking device for marking distance between steel bars of road bridge

The invention relates to a point-making distance-marking device for marking the distance between the steel bars of a road bridge to solve the problem that a traditional point-making distance-marking device is liable to damage and unclear in marked points. The point-making distance-marking device includes a vehicle body, wherein a material box is mounted on the vehicle body; a side wall of the material box is provided with a fixing block; a piston cavity is disposed in the fixing block; a vertical rod which can be ejected downward is installed in the piston cavity; a slidable piston is mountedon the vertical rod; a horizontal first through hole is disposed on the vertical rod; the piston slides relative to the vertical rod to close or open the first through hole; the vertical rod has a second through hole therein communicating with the first through hole; a plurality of liquid inlet holes are formed in the side wall of the fixing block; the outer wall of the material box is provided with a rotatable annular sl