The utility model relates to the field of safety warning, in particular to a highway construction safety warning device which comprises a base and further comprises a warning board, a water containing tank is installed at the upper end of the base, supporting seats are fixedly installed at the positions, located on the two sides of the water containing tank, of the upper end of the base, adjusting rods are arranged at the tops of the supporting seats, and limiting assemblies are arranged at the tops of the surfaces of the supporting seats. A bearing seat is fixedly installed at the upper end of the adjusting rod, connecting shaft rods are fixedly installed at the left end and the right end of the warning board, the connecting shaft rods are rotationally connected with the bearing seat, and a mounting seat is arranged at the upper end of the bearing seat; the water containing tank is located on the base, when the warning board is placed, clear water is injected into the water containing tank, the weight of the base is increased, the stability of the warning device is improved, the warning board is prevented from toppling over, after the water containing tank is filled with the water, water tank collision is formed, anti-collision protection is improved, meanwhile, the position of the adjusting rod can be adjusted, the height of the warning board can be changed, and when the warning board is stored, the warning board is convenient to store. And the warning board is turned over to cover the water containing tank, so that synchronous storage is realized, and the practicability is improved.