The invention discloses a real-time hot steel blank spray machine set based on PLC, which comprises a spray main machine and an electric controller. Wherein, the spray main machine has a slide frame, on which the traverse vehicle, the displacement sensor, the transverse displace cylinder, and the transverse displace controller are arranged; the transverse vehicle has a longitudinal vehicle, and a big inlet cylinder; the longitudinal vehicle has a sprayer element, and a small inlet cylinder; the spray main machine has a coating material feeding system; the electric controller uses the PLC control system which is connected to the industry control computer, the on-place detector, the electromagnetic valve condition detecting module, the transverse displacement controller, the feeding belt control switch, and the electromagnetic valve. The invention via improving the mechanical structure of sprayer, and using PCL control system, realizes the full-automatic, accuracy and online real-time multiple digit continuous mark in high temperature, to confirm the sharpness of mark, and apply the long time operation of spray machine set in bad condition. The invention can improve the automatic level and the quality management level of steel blank.