Systematically described in this paper are characteristics of pyrites from the Xiangshan iron and pyrite deposits, such as their modes of occurrence, chemical composition, physical properties, unit cell parameters, infrared spectra and sulfur isotopic composition. The pyrites might be classified into two types. TypeⅠis statistically characterized by very fine_grained texture (0.01~0.1mm across), while TypeⅡis somewhat coarser (0.05~0.5 mm across) than TypeⅠ. Four pyrite samples show N_type electric conduction pattern with large variable pyroelectric coefficients (-97.5~246.5μV/℃), and one sample shows P-type. Unit cell parame- tersa0= 5. 41487 ~ 5. 41883°A, and the crystallochemical formula is Fe0.9946Co0.0017 Ni0.0037)1.0000S2.0279. Different types of pyrites show apparently different strong key absorption peaks with high absorption value features. In this area, every type of pyrite has relatively rich sulfur but poor Fe. Trace elements and REE geochemistry indicate that pyrites are enriched in Co, Ni, V, Ti, Cu, As, and Co/Ni ratios of all pyrites fall in a narrow range of 1~10; As/Se ratios of all pyrites range from 1.33 to 5.50.∑REE values of all pyrites are from 2.2×10-6 to 17.33×10-6, showing distinctly low Ce (δCe 0.62~0.78) and Eu (δEu 0.62~0.81). Sulfur isotopic compositions of all pyrites range from -2.11‰to 17.11‰. These data further demonstrate that these pyrites were formed by volcanic hot water deposition and that the formation of Xianshan pyrite deposits is attributed mainly to volcanic deposition.