焊接作为钢结构连接的重要手段，焊接接头的疲劳性能关系到钢结构的安全。为了提高钢结构焊接接头的疲劳性能，该研究提出采用激光重熔处理焊接接头。为此，该文开展了Q355钢板对接焊接的焊态接头与激光重熔处理接头的高周疲劳试验，通过焊态接头拉伸试验确定了高周疲劳试验的应力水平，采用扫描电子显微镜进行了疲劳断口分析，根据试验结果拟合了焊态焊接接头与激光重熔焊接接头的应力-寿命（S-N）疲劳曲线，并与规范疲劳公式进行了对比。试验结果表明：激光重熔处理可以改变焊接接头疲劳断裂的位置，避免焊接接头在焊趾处产生疲劳破坏，并显著提升焊接接头的疲劳寿命，平均提升幅度介于244%~499%之间；疲劳断口分析表明，焊态接头主要存在棘轮状裂纹源和少量次表面裂纹源，激光重熔处理接头主要存在转角裂纹源和边缘裂纹源；与规范对比结果表明，美国钢结构规范ANSI/AISC360-22、欧洲规范EN 1993-1-9：2005和海上钢结构设计推荐方法DNV-RP-C203给出的疲劳性能设计曲线可适用于焊态接头的疲劳性能，而对于激光重熔处理的焊接接头疲劳性能均偏于保守。

As a crucial method for connecting steel structures, welding plays a vital role in ensuring structural integrity, and the fatigue performance of welded joints directly affects the overall safety of steel structures. To enhance the fatigue performance of welded joints in steel structures, this study proposed the use of laser remelting treatment on the welded joints. For this purpose, this study conducted high cycle fatigue tests on the as-welded joints and laser remelting treated welded joints of Q355 steel plate butt welding. The stress levels for high-cycle fatigue tests were determined through tensile tests on as-welded joints. Fatigue fracture surface analysis was conducted using scanning electron microscopy (SEM). Based on the experimental results, stress-life (S-N) fatigue curves were fitted for both the as-welded joints and the laser-remelted welded joints, and the results were compared with standard fatigue design curves specified in relevant codes. The experimental results show that laser remelting treatment can change the location of fatigue fracture in welded joints, prevent failure at the weld toe and thereby significantly improve the fatigue life of welded joints, with an average increase of 244% to 499%. The fatigue fracture analysis show that there were mainly ratchet crack sources and a few subsurface crack sources in the as-welded joints, and there are mainly corner crack sources and edge crack sources in the laser remelted joints; the fatigue performance design curves provided by the American Steel Structure Code ANSI/AISC360-22, European Code EN 1993-1-9:2005, and Recommended Method for Offshore Steel Structure Design DNV-RP-C203 can be applied to the fatigue performance of as-welded joints, while these curves tend to be conservative for laser-remelted welded joints.