The work aims to solve sagging and flyoff of rust liquid occurring when bare weathering steel is firstly used. A new rust layer stabilizer was prepared for new weathering steel surface. Effects of rust layer stabilizer on rust layer structure and corrosion resistance of the weathering steel in the stimulated marine atmosphere were investigated by performing periodic immersion cyclic corrosion test, rust microscopic analysis and electrochemical testing. The treated rust layer of weathering steel was divided into compact and continuous inner rust layer and outer rust layer. After 168 h of indoor accelerated corrosion, weight loss corrosion rate of the weathering steel was reduced to 3.31 g/(m2?h) from 5.71 g/(m2?h) (compared to bare surface) by nearly 42%. The rust layer resistance of treatment steel increased up to 167.7 Ω?cm2 from 96 Ω?cm2. The rust layer resistance increased from 96 Ω?cm2 to 167.7 Ω?cm2 by nearly 75%. In the treated rust layer of weathering steel, Cr element was present on the interface between rust layer and substrate in the form of α-(Fe1?xCrx)OOH, and it aggregated in interface between inner rust layer and the substrate. The new rust stabilizer can obviously improve rust structure of the weathering steel, refine rust grain, and hinder permeation of Cl?, which contributes to rapid generation of compact, continuous and stable protective rust layer on surface of weathering steel.