分析了导致压力管道超声波测厚过程中数据发生异常的原因，并重点分析了管壁外表面粗糙度对超声波测厚结果的影响。使用了不同频率的超声波分别对不同表面粗糙度的压力管道试样进行了测厚，对比了各底面回波的脉冲宽度和延迟时间。试验结果表明管道外表面粗糙度对超声波测厚结果具有明显影响:表面粗糙较大时，测厚准确度下降。

This paper discussed the reasons that result unusual data during the testing work, and studied the influence of the pipeline outside surface roughness on testing result. Ultrasonic waves were used with different frequencies to test thickness of different roughness samples, and the width and delay time of the bottom echo pulses were compared. The results make it clear that pipeline outside surface roughness has obviously effect on the thickness testing result.