In this paper, the typomorphic peculiarities of pyrite in Dachang ore field of Guangxi, China, have been investigated according to chemical compositions and physical properties. It is showed that typomorphic peculiarities of pyrite in Dachang ore field are: higher in S/Fe ratios, richer in As and Se, poorer in Co, Ni and Te, Co/Ni<1, higher positive thermoelectric coefficient, higher unit cell a0 and weak paramagnetism. The microelements of pyrite show that the mineralization of Dachang ore field is related to magmatic hydrothermal solution, and also indicate the evolution trend of mineralization. The different types deposits in the ore field can be distinguished by using Sn/Cu ratios of pyrite. The As-rich pyrite is one of the characteristics of cassiterite-rich ore.