Abstract: Previously, researchers employed electron probe microanalysis (EPMA) furnishedwith LDEB or LDE3H to establish a quantitative analysis approach for the Be content in berylliumsilicates, beryllium oxides, and beryllium borates. Nevertheless, a quantitative analysis method forthe Be content in beryllophosphate minerals is still lacking. At present, when EPMA equippedwith LSA300 crystal is used to analyze beryllophosphate minerals, the higher-order peaks of Pwill raise the upper background value of the Be Kα peak, resulting in inaccurate measurementresults of Be content. In this study, the EPMA equipped with LDE3H crystal was used to explorethe optimal quantitative analysis conditions for herderite in Shiziling granite in Jiangxi Provinceby using different accelerating voltages and probe currents. The experimental results show that theoptimal EPMA quantitative analysis conditions for herderite are: acceleration voltage of 10kV, andprobe current of 20nA. Under these conditions, the average content of P₂O₅, BeO, CaO, F is43.23%, 15.39%, 33.89%, and 7.94%, respectively, and the standard error of BeO is 0.3%. It isfound that the EPMA equipped with LDE3H crystal can set a suitable Be background to eliminatethe interference of the higher order peaks of P. In addition, the difficulty of Be measurement isrelated to Be characteristic X-ray, crystal structures and chemical composition of Be minerals. Theexploration of a quantitative analysis method of herderite solves the problem of interference of Pelement when the EPMA accurately quantifies the Be element of beryllophosphate minerals, andfurther improves the accuracy of the measurement of beryllium content by EPMA.