The three carbonate rocks of bank facies,tidal flat facies and karst zone facies of the Triassic period are widely  spread in Lower -Middle Yangtze Region. According to their lithologic charactes, diagenetic typs, diagenetic fabrics, porosity properties and diagenetic environments etc. the diagenetic features of the kinds of three carbonate rocks are compared. Diageneses of grainstones of bank facies rocks are cementation, dolomitization and solution by the function of vadose and underwater current diagenetic environments of marine water and fresh water. The carbonate rocks of tidal flat facies are commonly composed of metasomatic dolomilites and evaporites rich in gypsums. The dolomitization is chiefly in association with penecontemporaneous by the replacement through capillary concentration and vaporation of marine water of high salinity in vadose zone. Dedolomitization, degypsification and solution develop in vadose and underflow diagenetic environment of meteoric fresh water.The dominative rocks of karst zone are carbonate-evaporites and karst cumulate breccias. The types of diageneses are characterized by penecontemporaneous dolomination under the action of strong evaporative marine water during the early stage of diagenesis. The karst dolomitization which occurs in the late diagenetic stage under the epidiagenetic freshwater diagenetic environment.
Because of secondary porosity development due to main diageneses mentioned above, so these diageneses play a dominant role for the kinds of three carbonate rocks becoming prospect reservior beds.