Butt welds are widely used in various engineering structures, and their effective integrity inspection is crucial for ensuring structural safety during service. However, conventional bulk ultrasonic testing methods suffer from low efficiency and heavy reliance on operator expertise, highlighting the need for more efficient alternatives. The SH?-like guided wave (zero-order horizontal shear wave) propagating along welds is considered ideal for high-efficiency weld inspection. Nevertheless, its application to thick-walled welded joints faces challenges such as low signal-to-noise ratio (SNR) and defect identification difficulties. To address these issues, this study proposes a novel baseline-free method for rapid butt weld inspection. The fundamental principles of the methodology are first introduced, followed by a demonstration of its implementation via finite element simulation. Experimental validation confirms the method’s effectiveness. Results indicate that the proposed approach offers significant advantages, including baseline-signal independence and high inspection efficiency, making it suitable for rapid inspection of butt welds in large-scale engineering structures.