Research on hydrothermal alteration mineral and mineralization type of primary tin was conducted in Pengarem village, South Bangka District. This research attempted to find out the type and mineralogy alteration of the site. The methodology involved lithological and structural observation, and X-Ray Diffraction (XRD) analysis. Litho logy constructing the bed was commonly sandstone unit. The developing alteration in this site consisted of argilic zone that characterized by clay minerals such as kaolinite and ilite. Primary tin mineralization developing in this site was polymetallic vein mineralization. The veins developed in sandstone unit, had relatively small size, and spreaded locally. The veins were consisted of quartz unit carrying tin mineralization (cassiterite) and associated with zinc oxide minerals that were ilmenite and hematite. The typical tin mineralization in this site was mineralization in gozzan unit, and was the result of supergene process carried by mineral cassiterite that associated with minerals iron oxide such as ilmenite and goethite.