We try to figure out the complicated process of diagenesis by studying a whole diagenetic system, which are composed of the deeply buried (3100∼3300m) lenticular sandbodies and the surrounded shales. We used 141 core samples, including sandstones and shales, and the analysis of thin section, X-Ray Diffraction, Scanning Electron Microscopy and Cathodoluminescence Micrography to analyze those samples' diagenesis heterogeneity. We found the lenticular sandstones got high porosity (20%) at the interior and low porosity (4%) at the SSC. The reason for low porosity was the present of carbonate cements. Shale supplied the source for a portion of the diagenetic cements near the SSC in the whole diagenetic system. Within sandstones and shales of late-stage illitization, unequal amounts of reactive components can diffusive transport in the whole diagenetic system. The whole diagenesis evolution result proved that shales play an important role in the process and must be considered in to sandstone diagenesis.