Abstract: Aiming at the problem of cross-folding defect occuring in boron-added low carbon cold-rolled strip produced by batch annealing process, the effect of chemical composition on this defectwas analyzed by microstructure characterization and tensile property testing. The results show that the atomic fraction ratio of nitrogen to boron (y(N)/y(B)) has a significant effect on the cross-folding defects of cold-rolled B-added mild steel, and the cross-folding defect problems are obviously improved with the increase of y(N)/y(B). The main mechanism is that with the increase of y(N)/y(B), the content of solid solution B in grain boundary aggregation decreases, and the content of solid solution carbon in the grain is correspondingly reduced. Therefore, the elongation at yield of the tensile curve of the test steel is reduced, and the yield effect is weakened, so as to avoid the occurrence of cross-folding defects.