Abstract: The pre-stretch specimens, whose dimension conformed to the requirement of GB/T 4160-2004, were easy to neck or break at the clamping section before the pre-stretch strain reached the stipulated strain, and the tests failed. In order to avoid the above situation, the tensile tests with 5% and 10% straining and Charpy impact tests at a series of temperatures were carried out on the specimens whose shape and cross-section dimension were different from those of the standard specimens. The results show that: the dimension of pre-stretch specimens had no significant effect on the results of strain aging sensitivity test; different cross sectional dimensions of pre-stretch specimens could be acceptable during the strain aging sensitivity test of steel materials, such as rectangular specimens with grip ends of the tension test at ambient temperature.