This paper studies characteristics of geological modes of occurrence, petrography and mineralogy of tourmaline bearing rocks as well as mineral chemistry of tourmaline, and deals with the genesis of tourmaline. Four modes of occurrence of tourmaline are recognized: (1) tourmaline accompanied with Beiyu granodiorite and granite porphyry, (2) veinlike tourmaline bearing rocks in metamorphic strata, (3) striped tournaline bearing rocks, and (4) tourmaline veins in the host rocks. The main mineral chemical characteristics of tourmaline are as follows: (1) the contents of FeO and MgO vary considerably, and there are four types of mineral species: Fe tourmaline, Fe rich tourmaline, Mg Fe tourmaline and dravite;(2) the relative variations of Al 2O 3, FeO, MgO contents are closely associated with types of host rocks and geneses of tourmaline;(3) Na 2O, Al 2O 3 and FeO, TiO 2 contents of tourmaline assume growth and decline relationship in granite porphyry and granodiorite, which corresponds with the mutual compensational relation of chemical composition of the host rocks. There exist three genetic types of tourmaline: (1) tourmaline formed by post magmatic hydrothermal solution at the late stage of Beiyu granitoid plutonism , including striped tourmaline bearing rocks;(2)tourmaline formed by metamorphic fluids in Zhongtiao Group; (3) tourmaline formed by hydrothermal alteration at the stage of copper mineralization and occurring in the host rocks and the near ore rocks. The third type of tourmaline is characterized by veinlet form, fine grain size, rich MgO and poor FeO and mineral assemblage of quartz, calcite, biotite, pyrite and chalcopyrite. All these characteristics constitute important ore prospecting indicators.