The Lujing deposit is a typical veined Pb-Zn deposit in west Damingshan area, and its orebodies are located in the Cambrian strata and strictly controlled by faults. Based on detailed field geological survey as well as analysis and interpretation of fluid inclusions, sulfide mineral chemistry and S isotope, the authors investigated ore-forming fluid properties and sources of ore-forming mineral. Petrographic observations reveal that the inclusions at stage Ⅱ of Lujing deposit primarily belong to liquid-rich, single-phase aqueous fluid inclusion. Microthermometric measurements indicate that homogenization temperatures are 237~281℃ (256℃ on average), with corresponding salinities of 3.54%~12.69% (8.39% on average). Electron microprobe analysis indicates that, characterized by high content of Fe, Cd and Cd and low content of Mn, Ga and Ge, sphalerites should belong to high temperature iron sphalerite. The δ³⁴S values of sulfides vary from -1.9‰ to 4.4‰ (1.7‰ on average), close to zero on average, which indicates that sulfur of the sulfide was derived from the magmatic source. Based on ore-forming geological characteristics, fluid inclusions, sulfide mineral chemistry and S isotope, the authors hold that the Lujing deposit should belong to hydrothermal vein type Pb-Zn deposit, that mineralization of Lujing was closely related to the magmatism, and that the deposit was formed in late Yanshanian period.