The chemical composition of LaNi5 needed to be measured rapidly and sensitively to control the hydrogen storage capability of the material. Glow discharge mass spectrometry (GDMS) was an excellent candidate for the measurement of LaNi5 due to its high sensitivity, simple preparation, and the capabilities of simultaneous analysis of multiple elements as well as direct analysis of solids. In practice, the application of GDMS to LaNi5 analysis was constrained by the difficulties in sample preparation arising from the morphology of LaNi5 and by the lack of the matrix-matched materials. Herein, an analytical method for the determination of 25 impurities elements in high-pure LaNi5 particles was established using GDMS. The zirconia mortar was selected as the tool for grinding the sample into powders by comparing the hardness and the introduced contaminants to those of other mortars. Under the optimized instrumental parameters, a set of relative sensitive factors (RSF) for calibration was established using nickel matrix based certified reference material, which was the analog of the matrix-matched material of LaNi5. This assumption was validated using corresponding standards with the relative error below 30% between the measured and the certified values. The previously reported universal RSFs (X. Wei, et al. Spectrochim. Acta, Part B, 2019, 154, 43–49.) were adopted for the absent elements in the available nickel standards. With this protocol, up to 25 impurity elements in LaNi5 were quantified, and the results were further validated by the other independent methods. Our work established a rapid and sensitive GDMS method for the quantitative measurement of 25 concerned impurities in LaNi5, improving the LaNi5 material analysis contents and efficiency. This method might also be applied to the sample preparation and the generation of RSFs of target element for the other complex analytes.