Abstract: Nanpu terrestrial shallow layer is a complex small-fault-block reservoirs in the fault basin of Bohai Bay, being one of the typical reservoir developed with horizontal wells. With the advance of horizontal well development technology, most of the reservoirs developed with horizontal wells are at high water cut and extra-high water cut stage. Through CO₂ huff and puff in horizontal well, remarkable effect has been obtained in increasing oil production in the past two years. In this article, the stimulation results through CO₂ huff and puff in horizontal well has been analyzed, the influencing factors on CO₂ huff and puff have been evaluated using the statistics principles by taking different single factor values. Through application of fuzzy evaluation method, the potential evaluation method for selection of horizontal well for CO₂ huff and puff in complex fault block has been developed, which provide an important guidance in selection of horizontal well for CO₂ huff and puff in similar type of reservoirs, and is significant for improveing the oil-field developemt effect with horizontal well.