In view of the issue of water flooding in the development process of horizontal wells in complex fault block reservoirs in Jiangsu oilfield, horizontal wells were divided into three types: local water flooded type, overall water flooded type and low liquid low efficiency type, based on the shape of horizontal well water flooding performance curve. According to the production characteristics and remaining oil distribution law for each type of horizontal well in the development process, incorporating methods such as physical simulation, reservoir engineering and numerical simulation, the differential treatment for enhanced oil recovery technology of horizontal well was studied. Technical countermeasures for EOR of different types of horizontal wells were formed, which has been widely applied in the field and achieves good effect. The results can provide technical reference for horizontal well treatment in other oil fields, and has important guiding significance.