Abstract: The content of sulfuris an important evaluation index for the performance of rare earth sulfides.The determination of sulfur content primarily involves the barium sulfate gravimetric method, iodometric method, and high-frequency infrared absorption method.Compared to the iodometric method, the barium sulfate gravimetric method can measure sulfur content in all valence states within rare earth sulfides.In contrast to the high-frequency infrared absorption method, it enables accurate determination of higher sulfur concentrations. The sample was subjected to sodium carbonate and sodium peroxide fusion, followed by hot water leaching by the barium sulfate gravimetric method. Alkali separation was employed to remove impurity ions such as nickel and rare earth elements. The filtrate was precipitated with barium chloride under acidic conditions (pH=1-3) to form barium sulfate. After filtration, washing, and calcination at 800 ℃ until constant weight, the total sulfur content in the rare earth sulfide was calculated based on the mass of the converted barium sulfate. The proposed method was validated through experimental testing. Comparative analyses were conducted using the developed method, high-frequency infrared absorption spectroscopy, and inductively coupled plasma atomic emission spectroscopy (ICP-AES) for sulfur content determination in rare earth sulfide control samples. Results showed that the measured values from all three methods were essentially consistent with the reference values.