Abstract: In order to improve the accuracy of quantitative analysis on an energy dispersive X-ray spectrometer (EDS), the optimal instrumental working parameters were searched based on theoretical analysis and experimental study. The basic requirements for sample preparation, accelerating voltage, collection time and the analysis of regional were discussed and the impact on the energy spectrum and the best option parameters were studied. For example, a low accelerating voltage should be used for a light element analysis, and excessive analysis time could induce more carbon deposition after prolonged electron beam bombardment. More satisfactory results were obtained by choosing reasonable parameters and the accuracy of the quantitative test can be improved.