Transverse buckling of a strip in continuous annealing production line (CAPL) has been investigated. Transverse buckling occurs when the induced compressive stress resulting from non uniform longitudinal stretching in the strip exceeds a critical buckling stress. The MARC software has been used along with a buckling nonlinear geometrical analysis. The mechanisms of major factors, such as roll profile, flatness, strip size, transverse distribution of temperature, welding seam and strip track-off are reported. The average hour output increased by 5.89% through a series of technical developments.