Abstract: Based on the analysis of regional geological background, the sedimentary characteristics of Taiyuan formation of Carboniferous system in Daniudi gas field are analyzed. The results indicate the sandstone of Taiyuan formation has the microcosmic characteristics of high quartz grain content and good separation. The macroscopic distribution has the strip spreading point of relatively straight, narrow width and relatively large thickness characteristics. The reservoirs in the Taiyuan formation developed longitudinal cross-bedding,feather-like cross-bedding, 'one-way' flow structure,vein-like bedding, wavy bedding and lenticular bedding,etc., which were formed by typical tidal action. Combined with the reservoir rock particle size analysis and well logging facies analysis, it can he identified that the shallow grey, grey-white massive bedding quartz sandstone facies, light gray cross-bedding quartz sandstone facies, gray wavy bedding fine, siltstone facies and dark gray microcrystalline limestone facies.According to the analysis of the same type of rock facies,Taiyuan formation is deposited in tidal flat facies intertidal zone, and develops microfacies, such as tidal channel, tidal creek, tidal pool, mud flat and mud swamp.The favorable reservoir is tidal channel and tidal gully sandstone.