The Yushui deposit is a high- grade copper (bornite and chalcopyrite) deposit with main orebodies occurring between the dolomite of the Upper Carboniferous and quartz sandstone of Lower Carboniferous. The detailed field geological survey confirmed the existence of Carboniferous tuff in the footwall of the massive orebodies, and newly discovered volcanic mounds and volcanic conduits and vents. We also confirmed that the red hematite- siderite- jasperite combination is an exhalative- sedimentary rock, which covers the top of the massive orebodies and extends well beyond the margins of massive sulfide. Therefore, the sequence of the stratiform orebody is determined from bottom to top: quartz (gravel- bearing) sandstone interbedded with tuff→massive copper- lead- zinc sulfide orebody→hematite- siderite- jasperite and other exhalative- sedimentary rocks→dolomite, showing that the ore- bearing rock series has the characteristics of “trinity”: volcanic rocks- massive orebody- exhalite combination. The stratiform orebodies show typical “double- layer” structure: the upper part is a massive orebody, and the lower part is a cylindrical ore- bearing alteration body, which composed of a funnel- shaped fluid conduit system and its disseminated and network mineralization. Fan- shaped sulfide- containing quartz veins are developed around the main fluid conduit, and do not cut through the overlying massive orebody and dolomite of hanging wall. Synsedimentary faults (synvolcanic faults) that control the thickness of the orebody and tuff and the plastic flow of the copper orebodies have been newly discovered. The above geological evidence demonstrates that the Yushui deposit is a submarine exhalative sedimentation massive sulfide deposit which formed in shallow water environments. This conclusion will inspire VMS deposit studies, has important scientific value globally, and can be used as a reference for prospecting for concealed VMS copper polymetallic deposits in similar geological background areas in South China.