Abstract: A simulation analysis on the stainless steel butt joint of the longitudinal seam of the inclined cone jacketed tube in the liquid separation tank was conducted. Through acoustic field simulation analysis, an initial inspection process was obtained. Then, the process was optimized through defect response simulation analysis. The optimized PAUT detection process and the standard radiographic inspection process were verified respectively on the simulated test block, and the detection results were compared and analyzed. The results showed that the optimized PAUT inspection process had a good detection effect, providing an effective ultrasonic solution for the inspection of the stainless steel butt joint of the longitudinal seam of the inclined cone jacketed tube in the liquid separation tank.