Abstract: Thin plates are easy to buckle when heated, which limits the application of laser welding of thin plates.Typical distortion behaviors of thin stainless steel plates with two different thicknesses, 0.8 mm and 1.5 mm, were recorded by a digital camera. The recorded behaviors consisted of both amplitude and direction of the disfortion.The two different sheets showed different distortion behaviors, and the buckling mechanism was analyzed respectively. Moreover, according to the two different buckling mechanisms, a backside dynamic cooling technology was introduced to control the buckling distortion. After experimentally optimizing cooling parameters, the cooling distance the and water flow rate, the welding distortion was controlled very well.Influnce of proper restriction on bulking was discussed.