Abstract: Mohailaheng lead-zinc deposit is located in Jieduo back-arc foreland basin of the northrim ofthe north of Sanjiang metallogenic belt,its main ore-bearing horizon is the lowercarboniferous supported heteropoly group of carbonate group,Containing ore formation andNWW fracture are important ore-controlling factors. Ore minerals are mainly galena,sphalerite,limonite and so on. The research results of lead isotope in the study area show that lead quarries μ is 9.27-9.77, the average of μis less than 9.58,the average of ωis 39.99,lead isotopic composition has the characteristics of normal lead evolution. Lead quarries ²⁰⁶Pb /²⁰⁴Pb is 18.51-18.92, the average of ²⁰⁸Pb /²⁰⁴Pb is 38.64, with the characteristics of stable isotopic composition. Lead mineralizing materials have the characteristics of crust-mantle evolution in Zartman lead isotope structure. Based on the above analysis, Mohailaheng lead-zinc mine mainly occurs in thick-super thick layers of carbonate rocks,and the mineralization had no direct relation to magmatic activity, which reflected that the lead came from lead mine construction of the upper earth′s crust. lead containing formation or subprime fracture intersection part are favorable met allogenic or prospecting positions.