Abstract: The large scaled Mengentaolegai Ag-Pb-Zn deposit in Inner Mongolia occurs in the center of the Late Permian granite complex. The host structure is a group of E-W-trending brittle fault zones. The metallogenesis experienced four stages, forming 44 ore veins in three levels, including 9 main orebodies, 9 large branch orebodies and 26 small orebodies. The deposit shows an obvious vertical zonation of Zn orebody, Ag-Pb-Zn orebody and Ag-Pb orebody from bottom to top. The commercial minerals are sphalerite, galena, pyrargyrite, canfieldite and native silver. The useful elements are mainly Zn, Pb and Ag, with associated In, Cd, Ga, Cu, Sn and Au. It is believed that the genesis of the deposit belongs to fissure-filled mesothermal Ag-Pb-Zn polymetal type, with evident prospecting indicators.