Abstract: No. 1 Section of the Kapushaliang Group is dominated by the sedimentary sequencesof fan delta, The microfacies of gas reqervoir sand body mainly consists of channel bar andsubaquatic split-flow channel and they should be attributed to braided river plain and sub-aqtiatic braided plain stibfacics,respectively,They are vertically charactcrized by multiplesuperimposition and latterally by frequent migration,in occurrence of well-sequentialsheet-geometry, Du ring the evolution on of porous reservoir,the katogene by diagenesis includes compaction,pressure solution, cementation and replacement of carbonate and quartzsccondary enlargement while the construction consists of remagenesis and deep dissolution.The reservoir spaces of thc sandstones are dominated by secondary solution openingsand percolation paths are pore throats associated with fractures,briiiging about a of thereservoir porous type.