The energy dispersive X-ray fluorescence (EDXRF) spectrometry technology is employed to rapidly determine the sulfur content in coal, while the better accuracy of measurement is limited by the matrix effect and the edge effect. A detailed computational model using the Electron-Gamma Shower (EGS) Monte Carlo code is set up, in order to study the X-ray fluorescence intensity under different tube voltage and for different diameters, thicknesses and sulfur concentrations of the coal sample. Simulation results show that the appropriate tube voltage is 15 kV, and the diameter and thickness of the sample are over 1.04 cm and 0.05 cm. According to the simulation results, experiments are carried out to obtain the relationship between the X-ray fluorescence intensity and the sulfur concentration in coal. The experimental results and the EGS simulation results agree well after the amendment of detection efficiency. These results will lay the basis for the subsequent designing of an online fast analysis system for the concentration measurement of sulfur in coal.