In this paper, the authors discuss the control factors of the gas reservoir of Paleozoic group.Combined with the reservoir characteristics,superface structures,sedimentary facies and diagenesis,etc., the paper concludes the accumulation regularity of natural gas pools in Ordovician Majiagou Formation (O1m) of the Sulige area in Ordos Basin and an advantageous direction of gas exploration of Ordovician is obtained.During the gas exploration in Paleozoic group,the authors think that the next two points should be considered.Firstly,people should pay attention to the areas between the paleo-hammock and the ancient groove (depression),and the well locations should be in O1m54-1 and O1m51-3.Secondly,the strong karst actions in the nose alar-like and nose uplift-like areas also should be taken into consideration.