Abstract: With numerous observations on thin sections of rocks and core casts from drillings,and the application of various analytical techniques including cathodoluminescence,scanning electron microscope and X ray diffraction,the paper made a detailed study on the diagenesis,pore evolution and the characteristics of diagenetic sequence in Jurassic-Cretaceous reservoir sandstones,northern Jiangsu.It is concluded that the behavoir of the major Mesozoic terrestrial reservoir sandstones in Jiangsu is both controlled by depositional conditions and affected by burial diagenesis.Compaction,cementation and replacement and dissolution are most influential factors that control over the evolution of porosity,among which cementation and dissolution are of importance that will affect the formation of reservoir space directly.