内标法是激光诱导击穿光谱(LIBS)定量分析主要使用的方法之一，采用内标法进行定量分析的关键就是内标参量的选取。以Fe 438.35 nm 作为分析谱线，分别选取434~441 nm 光谱积分、Al 309.29 nm、Si 288.17 nm、Ca 317.9 nm为内标参量，对水泥样品中的Fe 元素进行定量分析，得到的定标曲线线性度分别为0.993、0.962、0.992 和0.846。通过分析各内标参量与分析谱线光谱强度比值随积分延迟时间的变化情况，以及针对每个样品选用不同的内标参量得到的多组测量数据的离散程度，得出采用内标法进行LIBS 定量分析时，应该选择在积分延迟时间附近光谱强度变化与待测元素的分析谱线最为相似的作为内标参量的结论。这样能有小减弱由于激光器时间抖动导致的定量分析误差，提高定量分析精度。

The internal standard method is one of the main methods used in laser-induced breakdown spectroscopy (LIBS) for quantitative analysis. The key of the internal standard method for quantitative analysis is the internal reference selection. Fe 438.35 nm is selected as the analytical line. Area of 434~441 nm、Al 309.29 nm、Si 288.17 nm、 Ca 317.9 nm are selected as internal standard parameters for quantitative analysis of Fe in cement samples. The correlation coefficients of calibration curves are 0.993、0.962、0.992 and 0.846，respectively. By analyzing the intensity ratio of each internal standard element and Fe 438.35 nm at different delay time, as well as the dispersion of multiple measurement data of each internal standard element, it is obtained that when LIBS is used for quantitative analysis with internal standard method, the internal standard element which has similar changes to the analytical spectral line in the vicinity of delay time should be choosen. This can effectively decrease the quantitative analysis error caused by laser jitter and improve the accuracy of quantitative analysis.