In the Xinchang-Yongjia silver (lead-zinc) ore belt, there mainly occur the large to medium-sized Haoshi, Bamao, Dalingkou and Wubu silver deposits or silver-bearing lead-zinc deposits. On the basis of researches on these typical deposits, the mechanism of leaching-drawing mineralization of Mesozoic geothermal water and the related model are put forward in this paper in the light of the time interval between rock and formation ages as well as hydrogen, oxygen, sulphur and lead isotope geochemical characteristics. The major metallogenic process occurred in volcanic rock layers. The ore-forming fluids are geothermal water coming from meteoric water and circulating at shallow layers. This geothermal water leached and absorbed ore-forming materials from its country rocks during its flowing (such metallogenic elements as silver, lead-zinc and sulphur mainly came from consolidated volcanic rocks), leading to the formation of meso - epithermal silver deposits.