Keywords: 
• organic petrography /
• exi no-vitrnites /
• ultramicroliptinites /
• hydrocarbon potentias

Abstract: tential of different assemblages of macerals was studied. The hydrocarbon potential per unit orgyi ccar-bon of the exino}itrinites is high which proves the oil and gas prospect in the PRM B.Coal petrographjcal identification and fluorescence testing for organic macerals of Paleogene sour cerrocks in the Pearl River Mouth Basin( PRMB) were carried out by using com prehersive microscopymethod of combining transmitted light, reflected light and fluorescent light. The new technology ofTransmitted Electronic Microscope( TEM)was also applied to study ultramicroliptinites invitrinites. Py-rolysis simulation was used to evaluate the hydrocarbon potential of source rocks with different composi-dons of organic macerals.(1),A unique feature of macerals in the studied area was discovered, i. e. richexinites and sapropellinites are endedded in the vitrinite, and a new name, exino-vitrinite was given forthis kind of maceral. The exino-vitrinite was further divided into submacerals through integrating finerdivision of the amorphous;(2),Ultramicroliptinites were identified and quantitated under the highfoklT EM;(3),The source rocks were classified into three types and seven assemblages of organic ma corals,Among them the assenblages of A₂ and Bi are the primary ones, Bz the secondary. The exino-vitrinitesand ultramicroliptinites are the main hydrocarbon generating matter in the basin.(4),Hydrocarbon po