通过SRIM程序的快速损伤计算与全级联计算两种常用模式，对单元素靶材料进行粒子辐照模拟计算，分别利用基于损伤能量间接计算移位数的NRT位移模型方法和直接通过输出文件读取的方法获得移位数，并对数据进行相应的处理及分析对比，结果表明：对于单元素靶来说，在SRIM快速损伤和全级联两种计算模式下，利用NRT位移模型数值计算得到的移位数基本一致，都可以用于进一步计算得到可靠的位移损伤剂量（dpa）；而通过SRIM两种模式下的输出文件数据直接获得的移位数则有两倍左右的差异，要想得到相对可靠的dpa相关参数，需要根据不同辐照情况选取合适的计算模式。

The ion irradiation will cause different degrees of radiation damage to the target material. One of the important physical parameters to evaluate the radiation damage is dpa, that is, the displacements per atom. The Monte Carlo method based SRIM simulation program, which describes the collision and energy loss between ions and the target, is widely used to calculate many parameters related to particle beam irradiation. The number of atomic shifts per unit depth per incident particle can also be calculated as an important parameter in dpa. In this paper, the single element target material is simulated by two common models of SRIM program. The NRT mathematical model based on damage energy is used to calculate the number of displacements indirectly and the output file is used to get the displacements number directly. The results show that for the single element target, the displacements calculated by the mathematical model are basically the same under the two modes of SRIM Quick damage and SRIM Full cascade, which can be used to calculate the dpa reliably. The displacements obtained directly from the output file of the two modes have about two-fold difference. To get the reliable dpa parameters, it is necessary to select the appropriate calculation mode according to different irradiations.