The Huize lead-zinc deposit has become one of world-famous deposit for its extremely high reserves of ores and a large number of dispersed elements (Ge, Ga, Cd and In, etc.). The hydrothermal dolomite is the most important host rock in this orefield. On the basis of identification of typical sections in combination with geological logging and inclusion investigation of dolomites, the authors divided the dolomites in the ore district into burial dolomites and HTD (Structure Controlled Hydrothermal Dolomite). Some conclusions have been reached based on the study of the HTD dolomites: ① The formation of HTD was controlled by NE-trending compresso-shear interlayer fractures, and the HTD dolomites are especially well-developed on the upper side of the fracture. ② There exist large quantities of fissure (hole) gaps which reflect the intensity of diagenesis. ③ Dolomites show coarse grains, are pink, gray or brown in color, and exhibit unique spire, anhedral saddle shape, curved face saddle shape, curved face contact, intracrystalline microcracks and dissolved pores as well as wavy extinction and fog core bright side. ④ Saddle-shaped dolomites are thick layered and have geode filled with hot brine. They are associated with disseminated spotted pyrite and some other hydrothermal minerals. ⑤ Saddle-shaped dolomites with microcracks are divided into matrix metasomatic type and pore fracture filling type. In the narrow transition zone between HTD and limestone, they form zebra-shaped structure and brecciated structure. ⑥ HTD inclusions related to NW-trending faults are characterized by high temperature (250～438 ℃) and wide salinity range (3.4%～17.2%), whereas HTD inclusions related to NE-trending faults have high temperature (180 ～354 ℃) and low salinity (1.1%～5.9%). Through analyzing the driving mechanism of fluid, fluid properties, and indicators of mineralization, the authors revealed the diagenetic mechanism of HTD, i.e., under compression, the formation of HTD was controlled by NE-trending compresso-shear interlayer fissures: ① The regional fold and thrust constituted the deep dynamic mechanism of fluid migration. ② Hot brine fluids with acidic high temperature and salinity were concentrated in the thrust fold system. With the CO₂ boiling occurring on the upper side and in the expansion position of NE-trending compresso-shear interlayer fissures related to the thrust fold system, the thick-layered dolomites were formed. ③ Crack (hole) gaps reflect the intensity of diagenesis. ④ lithologic zoning, diagenetic strength and structural characteristics (microstructures) of HTD are indicators of orebodies.