The weathering steel has good resistance to atmospheric corrosion due to its compact and protective rust layer. It is the most practical way to reuse weathering steel after the rust-stabilizing treatment. The research on the structure, formation mechanism and process, and protection mechanism of the surface rust layer on weathering steel plays a fundamental role in the development of rust layer stabilization treatment and rust stabilizer. Firstly, the research progress of surface rust layer on weathering steel in recent years is reviewed. The weathering steel forms the compact inner rust layer with Fe3O4, α-FeOOH and amorphous oxyhydroxide (FeOx(OH), x=0~1) and the loose outer rust layer with β-FeOOH and γ-FeOOH through the dissolution of the matrix iron, the reduction of rust, and the reoxidation of rust. The inner rust layer and the outer rust layer forms the surface rust layer on the weathering steel. Compared with carbon steel, the surface rust layer of weathering steel has the characteristics including continuous compactness, anode passivation and ion selectivity which provided the weathering steel with good resistance to atmospheric corrosion. Next, the rust layer stabilization treatment method at home and abroad and their advantages and disadvantages are summarized, mainly including oxide coating treatment, iron oxide-phosphate treatment, shot peening + high temperature oxidation treatment and so on, but there are still a few problems, including the narrow application range, pollution, etc. Finally, the design idea of the rust stabilizer composition based on the role of alloying elements in weathering steel is proposed, and the further suggestion for the study on the rust stabilizer of weathering steel is proposed from the scope of application, environmental protection, and shortening of the stabilization period.