Maokou Formation of mid Permian is considered as one of significant gas producing formations in southern Sichuan Basin．Affected by the exposure and weathering leaching in Dongwu movement during the latest of mid Permian period，a typical weathering crust karst reservoir occurred in the marine carbonate of Maokou Formation．However，with the absence of accurate restore of the palaeokarst geomorphology，the knowledge has been affected of carbonate reservoir distribution developing in the Maokou Formation．The present work mainly analyses materials from drilling，logging and cores，classifying and correlating stratigraphy precisely，establishing isochronous stratigraphic framework，then choosing and confirming two stratigraphic interfaces which are distributing stably and almost isochronously in the whole region as the base levels，namely the subface of Mao 3 Member(the 3rd Member of Maokou Formation) and the top surface of Chang 1 Member(the 1st Member of Changxing Formation)，for restoring palaeokasrt geomorphology in the upper and lower erosional surfaces respectively．Additionally，depending on the residual and impression strata thickness data，it mapped contour map of residual strata thickness and that of impression strata thickness，then restoring，with the software called “Surfer”，the palaeoakarst geomorphology pre depositing Longtan Formation and the geomorphology of buried hill in the top of Maokou Formation post depositing Chang 1 Member．The geomorphology restored from the uppermost Maokou Formation， reflects that the geomorphology fluctuation and overall framework are accordant with the two methods，which can be classified into 3 secondary geomorphic units，containing karst platform，karst slope and karst basin，and the units can be further divided into sub geomorphic units including soluble hillock，monadnock，hillock clump，shallow depression and shallow valley．It is suggested that the karst platform distributed in a radial pattern originated from Luzhou palaeo uplift core，with the gently topography，hummocky hills，low and gentle ramp，but not with peak cluster geomorphology．And karst slope is found in the platform periphery，of which with gentle ramp stretch in northern and eastern region，meanwhile，those with abrupt ramp appear in western margin of karst platform．Moreover，the Karst basin presents along the line of Yibin Muchuan Suijiang，in southwestern of the region，with flat topography and featured with plain geomorphology．Finally，the relationship between the palaeokarst geomorphology units and large scale reservoir space as well as the condition of oil and gas production in Maokou Formation shows that，the palaeokarst geomorphology predominates the development and distribution of the karst reservoir，and further the production distribution of natural gas．It is indicated that karst fracture cavity reservoir can be developed both in karst platform and karst slope equally．Karst platform can be regarded as key exploration zone，and karst slope the most favorable zone．