Abstract: From the point of view of texture,Carbonate rocks are mainly composed of grains,mud,cement crystals and bio-framework.According to the character of the constituent elements and their relative content,limestones may be classified into three groups:granular micritic limestones,crystalline limestones and bio-framework-reef limestones,and in terms of the relative amounts of grain and micrite contents,granular micritic limestones may be subdivided into a number of smaller groups. The classification in this paper is made in consideration of both the textural components and their origin.