Aiming at the determination method of S element in soil，three kinds of instruments were used for comparative analysis to find the best analysis scheme. The analysis and comparison results showed that it was difficult to determine the low content of S by X-ray fluorescence spectrometer，but both the high-frequency infrared carbon-sulfur analyzer and the elemental analyzer could meet the requirements，and the analysis results were highly consistent，and the relative error was less than 8%. Therefore，in addition to the high-frequency infrared carbon-sulfur analyzer，the elemental analyzer is also an effective means to detect the S element in the soil.