GB/T 228.1-2010规定了使用直接法和移位法测定金属材料的断后伸长率。但铍材拉伸试样的横截面积和断后伸长率较小，若使用直接法测定，其断后伸长率随断口所在位置及试样断裂部分拼接状态的变化而变化，不具备唯一性；若使用移位法测定，虽弥补了直接法的不足，但操作较为麻烦。笔者介绍了利用横梁位移计算铍材拉伸试样断后伸长率的方法，可弥补上述两种方法的不足。通过试验及数据统计分析，证明此种方法可以准确快速地测定铍材试样的断后伸长率。

It is specified to use direct measuring method and position transferring method for the measurement of percentage elongation after fracture of metal materials in GB/T 228.1-2010. But the cross-sectional area and the percentage elongation after fracture of tensile specimens of beryllium materials were smaller. When the direct determination method was used, the percentage elongation after fracture did not have the uniqueness, because the percentage elongation after fracture varied with the fracture location and the splicing state of the fracture part of specimens. Although the position transferring method was a remedy for the direct measuring method, its operation was very complicated. Therefore, a method to calculate the percentage elongation after fracture of tensile specimens of beryllium materials by using the beam displacement was introduced, and it could make up for the shortage of the above two methods. Through the analysis of test data and statistics, it was proved that the method could measure the percentage elongation after fracture of tensile specimens of beryllium materials accurately and quickly.