Migration and precipitation mechanisms of metal elements in ore forming fluid are one of the important issues in the study of ore deposit. This paper summarized research results on the migration and precipitation mechanisms of lead and zinc in almost half a century. In general, three kinds of migration and precipitation models and three kinds of fluid migration driven models have been put forward for the MVT type Pb—Zn deposit. These patterns have different features, suitable for different ore deposits. Predecessors offered a number of basic data for migration and precipitation mechanisms research by the experimental of lead and zinc solubility. The study of the thermodynamic phase diagram and computer simulation provided semi quantitative data for the physical and chemical conditions of lead—zinc migration and precipitation. The study on element migration shows that in large carbonate hosted lead—zinc deposits, lead and zinc mainly exists by metal chloride complex in the acidic fluid. In precipitation mechanisms research, in addition to the cooling is related to temperature, dilution, boiling, water—rock reaction, REDOX can produce precipitation because of these effects can make the pH increases. As the synthesis of above mechanisms, mixing is the most likely mechanism for forming large size deposits. The essence is the high pH increase the more H2S molecular dissociate into HS-, and make the precipitation reaction.