描述了结构模块中不等厚焊接接头的超声检测方法，在声波从斜面入射或从斜面反射生成二次波时，针对缺陷难以准确定位的技术难点，采用几何分析方法进行定位修正，同时对影响定位精度的因素作简要的概述。

This paper describes the ultrasonic inspection technology for butt joint of unequal thickness in the structural modules. When the acoustic wave obliquely enters into or reflects on the angular surface, the location of defect must be modified in the method of geometric analysis because of the technical difficulty for location. The last part briefly summarizes the factors of influence on the positions accuracy. So, if we want to locate the defect correctly, we need qualified examiners, devices and appropriate methods.