Abstract: The edge peeling defect on surface of hot-rolled steel strip is a bottleneck problem to restrict the improvement of its surface quality. Aiming at the edge peeling defect in hot-rolled steel strip, the microstructure and chemical composition of the defect areas were analyzed by scanning electron microscopy(SEM) and energy dispersive spectrometer(EDS). Moreover, the statistical analysis of production data and the rolling test of flame-cleaning slab with prefabricated defect with were conducted in 2 250 mm hot continuous rolling line of Qian'an Iron and Steel Company of Beijing Shougang Co., Ltd., and the causes and evolution process of edge peeling defect in steel strip were clarified. The results showed that the accumulation and residual of slag convergence ridge caused by poor flame cleaning quality of cast slab could not be completely removed after heating in reheating furnace and descaling by descaler. The residual oxide layers from slag convergence ridge were partially embedded into the steel substrate during rough rolling and finish rolling while others remained on the surface of steel strip, ultimately forming edge peeling defect containing numerous oxidized spots with maximum thickness up to 150 μm. An industrial experiment was conducted to investigate the impact of edge convergence ridges removal by flame for slab on the quality of the hot rolled edge. Subsequently, process optimization was carried out and production data were continuously tracked. The results demonstrated that the improvement of flame cleaning quality to reduce the occurrence of intersection edge or the use of narrow-side non-cleaning process could reduce the incidence of edge peeling defect by 87%.