Significant economic sediment-hosted base metal deposits occur in Lanping, Changdu, Yushu and Tuotuohe areas of Sanjiang region in southwest China. The authors hold that they were formed during Indian-Asian continental collision and developed within the fold-thrust belt combined with thrust and/or strike-slip-related Cenozoic basins in the interior of the collsional zone. Ore bodies are hosted by carbonate and/or clastic rocks as hanging wall of the thrust fault, controlled by thrust-related salt diapir, second-order faults of the thrust fault, syn-ore hydrothermal karst, dolomitization, thrust-related breccias zones in carbonate, pre-ore karst, and fold-related intense cleavages/faults. The metals have Pb+Zn, Pb+Zn(+Cu+Ag), Cu+Co, or Cu associations in individual ore deposits. Sphalerite, galena, pyrite, ±marcasite, calcite/dolomite, and bitumen are common in the Pb-Zn deposits whereas sulfates and fluorite are abundant only in some of these ore deposits. The ores exhibit replacement and open-space filling forms. The main minerals in the Pb-Zn(-Cu-Ag) deposits include sphalerite, jordanite, galena, tetrahedrite, pyrite, calcite, and dolomite. They occur in veins or in hydrothermal karst as replacements and open-space fillings. The Cu deposits are composed of quartz + carbonate minerals + Cu sulfides (chalcopyrite, tetrahedrate, bornite and chalcocite) veins. The ore-forming fluids in the Pb-Zn and Pb-Zn(-Cu-Ag) deposits are dominated by basin brines with low temperatures (<210℃) and higher salinities . The ore-forming fluids are characterized by CO₂-rich fluids of metamorphic origin having relatively higher temperatures (180～230℃) and lower salinities in the Cu veins. Biogenic sulfate reduction±thermochemical reduction of sulfate by organic matter might have provided reduced sulfur for most Pb-Zn and Pb-Zn(-Cu-Ag) deposits whereas reduced sulfur in the Cu veins probably originated from volcanic rocks and sedimentary rocks. Upper crustal rocks contributed lead to all ore deposits. The base metal deposits in the Sanjiang region had no apparent affinity with magmatic activity. The authors tend to classify the Jinding, the Zhaofayong, the Dongmozhazhua, the Mohailaheng, and the Chaqupacha Pb-Zn deposits and the Pb-Zn(-Cu-Ag) deposits in eastern Baiyangping ore belt as MVT-like deposits, and to classify Pb-Zn(-Cu-Ag) veins in western Baiyangping ore belt and the Cu veins as polymetallic veins. Therefore, the Jinding MVT-like deposit, characterized by the tectonic setting of the interior of a continental collisional zone and thrust-controlling, can not be explained by the existing MVT genetic model.