Abstract: Chang 8 ultra-low permeable reservoir of Heshui area is an important potential exploration and development area in Changqing oilfield, with constant newly discovered hydrocarbon enrichment zones, and therefore, follow-up study should be carried out necessarily. Based on the existing research, in accordance with new drilling core, sandstone thin section, cast body thin section, scanning electron microscopy (sem) and X-diffraction data, the analysis has been carried out from the sedimentary and lithologic aspects. The results indicate the Chang 8 ultra-low permeable reservoir development is mainly affected by sedimentary microfacies, clastic composition, detrital grain size, compaction, cementation, dissolution and denudation action factors control, and among which, the compaction and cementation of reservoir densification are the main controlling factors, dissolution effect is a key factor to improve local reservoir physical property.