Abstract: Based on the core and thin section data, the measured physical properties and the well logging information, it is indicated that the Lianglitage reservoir is characterized by the matrix porosity and the macro?vugs and fractures superimposed development within 100 m below the top. The polycyclic thick reef?bank complex deposited in the suitable sedimentary environment of the Late Ordovician is favorable material basis for the reservoir?forming. The non?selective solution pores formed in the early diagenesis and near?surface karst play roles of superimposition and modification on such a reef?bank complex, which are the key factor for forming the ultra?deep and high?quality carbonate reservoirs in this area. The fractures formed by tectonic disruption in burial stage communicate the pores, and provide pathways for migration of multiple fluids. These fluids create dissolution or inhibiting cementation to the surrounding rocks, which could guarantee the reservoir and percolation capacity for the deeply buried carbonate rocks. Controlled by these factors, the pores evolution has undergo eight stages, of which three?stage oil?gas migration in the burial stage has good time?space configuration with the three stages of porosity development, hence forming the large condensate gas reservoir of ultra?deep and reef?bank complex of the Ordovician in Tazhong area