X-ray fluorescence spectrometry (XRFS) was applied to determine the concentration of seven elements (Si, Fe, Al, Ca, Mg, K and S) in the desulfurization waste ash from float glass furnace. To eliminate matrix interference, calibration samples with different mass fractions were prepared by compounding certified reference gypsum material with calcium hydroxide and calcium carbonate to simulate the composition of desulfurization ash. These samples were prepared using the fusion bead method. The standard curves for each element determined by X-ray fluorescence spectrometry (XRFS) were corrected using the Fundamental Parameters (FP) method. The accuracy of this method was verified using gypsum standards, with the highest absolute error between the test results and the certified values being 0.34%. The results indicated that this method exhibited excellent stability and was suitable for routine monitoring of waste ash in float glass factories as well as for subsequent solid waste utilization testing.