Continuous laser butt welding procedure expe-riments were carried out on A3 steel sheet to study the influence of different procedure parameters on the quality of welding.The results show that the width,depth and tensile strength of molten pool of welded joint increase with the increase of laser power. With the increase of welding speed,the width,depth and tensile strength of molten pool decrease gradually. The defocusing amount has little effect on the joint morphology and tensile properties. Effective welding can be achieved by keeping the tensile strength of the joint basically unchanged when the weld gap is below 50 μm.