Based on detailed petrographic and cathodoluminescence analysis，the cathodoluminescence characteristics and diagenetic stage division of carbonates in the Zhujiang Formation of the Pearl River Mouth Basin were studied. The results show that：①Carbonate minerals of the Zhujiang Formation generally emit weak CL indicating the leading role of seawater during diagenesis of Zhujiang Formation carbonates；while some samples show strong-very strong CL，which was locally influenced by non-marine fluids. ②Different rock types exhibit different CL features under the same conditions of cathode.Reef limestone are with two end-member CL of very weak-no visible or strong-very strong CL，whereas dolomitized reef limestone emits extremely weak CL. Bioclastic limestone are characterized by very weak or no CL in general，but a few sam? ples with terrigenous minerals show strong orange CL，while bioclastic dolomitized limestone shows the features of very weak or no CL with dolomite and weak-strong CL with non-dolomitized parts. ③Three or four phases of calcite cements development are recognized in turn：fringing fibrous calcite（or bladed spar calcite）-scalenohedral calcite-equant or blocky calcite-calcite filling in micro-fractures or distributing along the stylolites. Fibrous or annular leaf calcite commonly has no CL. ④Diagenesis of Zhujiang carbonates experienced four stages：penecontemporaneous sedimentary，contemporaneous sedimentary，early diagenetic and middle-late diagenetic according to the fabric of cements under different dagenetic stages and environments and their cathodoluminescence characteristics.