Bitumen is distributed extensively but not even in the Ordovician, southern oft-com:office:smarttags" />oft-com:office:smarttags" />Ordos Basin. It exists largely in fractures, intercrystalline pores, and solution pores or stylolites. According to the solid bitumen amount, abundance degree and thermal simulation experiment, paleo-reservoirs exist in the area. Their source rock was developed in a deepwater slope depositional environment of the middle Ordovician period. The amount of cracking gas is probably 3.6×10¹²~7.7×10¹² m³, providing sufficient gas source for hydrocarbon accumulation in the Ordovician, southern Ordos Basin.oft-com:office:office" />