Abstract: In this thesis, a method for the determination of major elements (including Na₂O, MgO, Al₂O₃, SiO₂, P₂O₅, K₂O, CaO, Fe₂O₃, MnO, and Ti₂O) in marine sediments by the X-ray fluorescence (XRF) spectrometry is optimized. In the experiment, the Li₂B₄O₇-LiBO₂ mixture m(Li₂B₄O₇)∶(LiBO₂)=67∶33 is adopted as the flux, LiNO₃ as the oxidant, and LiBr as the mold discharging agent. Under the above condition, the sample was prepared by melting. Meanwhile, the calibration curves were constructed, through applying the certified reference materials, such as soil, stream sediment, and marine sediment by X-ray fluorescence spectrometer. Moreover, the effects of flux, dilution ratio, remolding agent, melting temperature, and melting time on the determination results, were systematically studied. The results show that high-quality fuses were obtained under the following conditions: the sample and the mixed flux was uniformly mixed; the melt dilution ratio is 1∶10; the mixture was pre-oxidized at 700 ℃ for 200 seconds and melted at 1050 ℃ for 10 minutes. The loss on ignition (LOI) detection was not necessary while a relative large dilution ratio combined unknown LOI correction was adopted, which greatly simplified the test method. Testing with the marine sediment standard substance GBW07314, we find that the relative standard deviation (RSD) of each component content was 0.32%～2.05%, and the detection limit of the method was 70～270 ug/g. In the accuracy of the artificial standard sample, there was no significant difference between the measured value and the recommended value. The results reveal that the method is accurate and reliable, which can be utilized for accurate quantitative analysis of geological and geographic stream sediments, rocks, minerals, soils, and other samples., rocks, minerals, soils, and other samples.