On the basis of the combination features of rock and mineral using thin sections, X ray data, Elemental Capture Spectroscopy (ECS) logging, diagenesis features of sequence stratigraphic framework of the Upper Triassic Xujiahe Formation in central Sichuan basin were studied from two aspects of controlling of sequence boundary on diagenesis and evolution rule of diagenesis within different base level cycles. The results show the Xujiahe Formation can be divided into two super long term sequence cycles and five long term sequence cycles. The carbonate content in the sequence boundary for Xu 4 (Member 4 of Upper Triassic Xujiahe Formation) long term sequence cycles is significantly higher, coupled with common dissolution of the sandstones above the sequence boundary, producing relatively better physical property. Sediments resulting from the long term base level rising cycles Xu 4 are characteristic of coarse grains, low clay content, thick sand bodies, good connectivity, all of which better preserved the primary porosities during diagenesis process. While influence of organic acid water, which was controlled by sequence boundary, benefit to formation of secondary porosities. But during the falling hemicycle of base level, the connectivity of sand bodies became worse and content of clay was increasing, both of which are not favorable for primary porosity preservation and secondary porosity generation, producing worst reservoir property. This law in Xu 2 (Member 2 of Upper Triassic Xujiahe Formation) sandstones is overall consistent with that in the Xu 4 sandstones, but it is not evident because its deeper burial depth for Xu 2 sandstones and much complicated diagenesis. The research results above can not only provide guidance for the tracking contrast of high quality reservoirs in the studied area but improve the development of the diagenetic sequence stratigraphy theory.