Abstract: Aiming at the edge peeling defects occurring in cold-rolled typical low-alloy steels P280VK and 590DP, the formation mechanism of such defects was systematically investigated by means of metallographic observation, electron microscopy detection, thermodynamic calculation of precipitates and temperature field simulation of continuous casting slabs. Metallographic analysis and SEM-EDS results show that the defects exhibit typical intergranular oxidation characteristics, which can be traced to the inheritance of corner microcracks in continuous casting slabs. Based on FactSage thermodynamic calculation and continuous casting temperature field simulation, the mechanism that LF desulfurization induced nitrogen increment promotes the preferential precipitation of AlN at slab corners is revealed: the corner temperature in the straightening zone falls into the temperature range of massive AlN precipitation, resulting in grain boundary embrittlement and further the initiation of microcracks. During hot rolling, the crack propagation is restrained when AlN precipitation is below 0.01%, while the complete precipitation of AlN during cold rolling promotes the unstable propagation of cracks and eventually leads to edge peeling. Accordingly, technical measures are proposed, including controlling the nitrogen content in finished products (mass fraction of N less than 34×10^-6 for P280VK and less than 35×10^-6 for 590DP) and offline chamfering of high-nitrogen casting slabs. After application, the edge peeling rate of cold-rolled low-alloy steel is reduced from above 1% to below 0.22%.