Objective To reduce oxidation burning loss in furnace and increase product yield. Methods When a slab on the charging table (before it was fed onto loading roller bed and pushed into furnace) was less than 300 ℃, its top and bottom surfaces were cleaned up with roll type brush and air blow off set. Then oxide isolator resistant to high temperature was sprayed to its surface. It was then charged into furnace, and finally rolled into a hot strip coil. To reduce consumption of oxide isolator and improve the effect of spraying and the efficiency of operation, thin steel wire was changed to steel wire rope. The distance from stop valve to spraying nozzle (the section to be cleaned) was shortened from about 4 m to 0.2 m. Material used was changed from plastic soft pipes to brass hard ones with 5 mm inner diameter. As the loading roller bed was short, hot slabs over 300 ℃ must stay in the spraying cover. Besides, staying time was random. Therefore, if the set staying time was ≤10 min, spraying would continue; otherwise, spraying should be stopped and pipelines should be cleaned. But there were some troubles which caused non-uniform temperature of intermediate slab because of non-uniform thickness of painting when spraying system was restarted. Overflow valve was delayed to be closed for 0.5 s and pipe pressure was kept within 0.3 MPa. Results The product yield increased by over 0.3% and the consumption of steel coating per ton was controlled within 0.33 kg. Conclusion Optimization of spraying equipment structure, material and closing scheduling of overflow valve and control on system pressure will realize automatic spraying, produce painting with uniform thickness, save coatings and increase product yield.