The utility model discloses a device for controlling steel structure abnormality on a cold bed. The device comprises the cold bed, wherein a corrugated plate is arranged on the upper part of the cold bed, one side of the cold bed is provided with a heat-preservation cover which comprises a steel frame, the steel frame is internally provided with a heat-preservation material, one side of the steel frame is provided with steel frame supporting columns, a supporting column platform is arranged at the lower part of the heat-preservation cover and at one side of the cold bed, supporting plates which are parallel in pair are arranged on the supporting column platform and are in penetration connection through a rotation shaft, the steel frame supporting columns are in penetration connection with the rotation shaft and extend downwards, and the end parts of the steel frame supporting columns are in penetration connection with a rotation rod which is connected with a power device. By means of arranging the corrugated plate on the cold bed and arranging the heat-preservation cover capable of rotating around the supporting plates at one side of the cold bed, when hot-rolled round steel which is of a CrMnTi system and a CrMo system and has the diameter being below 60mm is cooled, the cooling speed can be ensured to be below 50 DEG C/min, so that upper bainite structures are prevented from being produced and product quality is ensured.