Abstract: In this paper, a simulation analysis was performed on the TOFD testing process for butt weld of a nuclear power plant ARE pipeline system. Through sound field simulation analysis, the preliminary testing process was firstly obtained, and then through the defect response simulation analysis the process was to be optimized. The optimized testing process and the standard recommended process were verified on the simulation block and the optimized TOFD testing results were compared with the radiographic testing results. The results show that the TOFD detection process was shown to have good detection effect, which provided an effective ultrasonic solution for the butt weld detection of ARE pipeline system.