Oxide scale is an inevitable product of hot rolled steel during production. There are a lot of surface quality problems resulted from the oxide scale. It is proposed that the research emphasis includes how to effectively utilize the oxide scale, rather than the descaling by pickling. In this paper, we described the development of the process of hot-rolled acid-free pickling high strength steel, introduced the method of improving the corrosion resistance of hot rolled steel by oxide scale and control means of granophyric defect on a plate. Finally, the key technology and development trend of direct reduction annealing and hot-dip galvanizing of acidfree steel sheet after temper rolling and wet spraying are put forward under the premise of eliminating acid pickling and pre-oxidation processes.