Abstract: The prospects for supercritical water gasification technology for hydrogen production from coal are vast. However, the development of this technology is hindered by the formation of toxic sulfides during the gasification process. Therefore, conducting research on the sulfur migration mechanism during coal supercritical water gasification is of great significance for establishing targeted control methods for sulfur in coal supercritical water gasification. The migration of inorganic sulfur, as an essential component of the sulfur migration mechanism during the coal supercritical water gasification process, is the focus of this study. Taking pyrite, a major carrier of inorganic sulfur in coal, as the research subject, molecular dynamics models for pyrite supercritical water gasification under various conditions were established. The study summarized the variations in key products such as H₂ and H₂S, and employed animations to track the desorption and transformation process of sulfur, obtaining migration pathway diagrams. The results indicate that increasing temperature not only promotes hydrogen generation but also suppresses hydrogen sulfide production, facilitating the release of sulfur from pyrite in the form of radical groups. Moreover, an increase in the number of supercritical water molecules promotes the detachment of sulfur atoms from pyrite and enhances hydrogen production. However, it does not stimulate the generation of hydrogen sulfide gas. Concerning sulfur migration, sulfur atom migration is divided into thermal dissociation desorption and water-assisted desorption. Thermal dissociation desorption occurs in the early stages of the reaction, while water-assisted desorption is the primary mode of sulfur atom migration. The final products include sulfur-containing groups such as HOS and H₂OS, along with H₂S gas. Sulfur-containing groups constitute over 80% of the total desorbed sulfur atoms. Another critical step in the evolution of pyrite clusters is the entry of oxygen atoms into the clusters. This process involves oxygen atoms from water molecules forming bonds with iron atoms, gradually moving from the outer to the inner regions of the clusters.