Abstract: Sub-sag in the northeast of Laizhou bay sag is an important hydrocarbon enriched region in Bohai sea area.Through comprehensive analysis of rock thin section,scanning electron microscopy(SEM),and reservoir physical property,a detailed study of deep sandstone reservoir diagenesis and pore evolution of Kenley 6- A structure has been carried out.The results show the deep reservoir experienced compaction,cementation,dissolution and etc.during burial process.According to the vitrinite reflectance and clay mineral evolution analysis,the diagenetic stage can be divided into four phases,namely early A phase,early B phase,middle A phase and middle B phase.Besides that,the pore evolution characteristics of each phase have been analyzed.