Warning device for road, bridge and tunnel building construction

The utility model discloses a warning device for road, bridge and tunnel building construction. The warning device comprises a warning plate, a base, a lifting mechanism, a warning mechanism and a reinforcing mechanism. The lifting mechanism comprises a bottom column and a telescopic rod, a second motor is installed in the center of the bottom of an inner cavity of the bottom column, the center output end of the top of the second motor is connected with a lead screw, the surface of the lead screw is sleeved with a sliding sleeve, two push rods are arranged at the top of the sliding sleeve, and the bottoms of the two push rods are symmetrically connected with the sliding sleeve. The top ends of the two push rods penetrate through the bottom column to be fixedly connected with the warning plate, the two sides of the top of the bottom column and the two sides of the bottom of the warning plate are fixedly connected with connecting pieces, the telescopic rod is located between the warning plate and the bottom col