With rough tin concentrate of Datun dressing plant as the study object, the authors used chemical analysis, X-ray diffraction analysis and optical microscopy analysis to investigate chemical composition, mineral composition and mineral assemblage of rough tin concentrate. The results indicate that the grade of tin in rough concentrate is 13.80%, and tin mainly exists in the form of cassiterite. The TFe possesses 30.78% in rough tin concentrate, and mainly exists in the forms of limonite and pyrrhotite, whereas the pyrrhotite is the main factor for the high sulfur content of the rough tin concentrate. The main gangue minerals are dolomite, tremolite, tourmaline, quartz, muscovite, fluorite etc., and gangue minerals and cassiterite have complex association relationship and encapsulation relationship. According to the results of process mineralogy, the rough tin concentrate of Datun dressing plant is suitable for pre-desulfurization by flotation, which is designed to desorb the sulfide, and the gravity separation process of flotation tailings should be adopted to improve tin grade and recovery. The results of the study provide scientific basis for process modification and rational exploitation of tin resources in Datun dressing plant.