The Zhujiang formation in Dongsha uplift of the Pear River Mouth Basin develops three sedimentary facies：littoral facies，carbonate platform，shallow sea continental shelf facies，among which，the carbonate platform is the main sedimentary facie which is consisted of reef，bioclast bank and plate.This paper thoroughly studied the carbonate reservoir of the Zhujiang formation from reservoir sedimentology based on core observations by applying various measurements，such as analyses of normal thin-section，cast thin-section，scanning electron microscope，X-ray diffraction of clay minerals，and this paper indicates that the main reservoir spaces are secondary pores，followed by primary intergranular pore，biological coelom hole and other primary porosity.By combining the measurement results with sedimentary evolution and diagenetic characteristics of basin，this study indicates that the reservoir’s development is influenced by the change of the sea-level，sedimentary facies and diagenesis.The platform edge and bioclast bank in Liuhua area are the favorable reservoir belt，and，the reef and bioclast bank of platform edge or platform point reef and bioclast bank of internal platform in Huizhou and Lufeng area are the less favorable reservoir.