Influenced by selective dissolution and fracture development degree，fault-karst reservoirs in Tahe Oilfield have the characteristics of extremely complex inner structure and obvious fracture-vug separation，which results in difficulty in understanding of water flood development. Based on the relationship between storage and flow in the oil reservoirs and five typical types of fault-karst，numerical simulation was carried out to study water drive law and remaining oil distribution characteristic of the five typical types of fault-karst from the aspects of injection velocity，injection-production position and fracture participation based on fluid dynamics. The results show that the displacement efficiency of the type“Y”faultkarst and the compound type fault-karst increases continuously when the injection velocity increases and the injection-production position changes from low to high. However，the displacement efficiency of type“V”fault-karst，type“T”faultkarst and belt-shaped fault-karst are hardly influenced by the above factors. The existence of fractures makes the displacement efficiency of the fracture-karst decrease. The distribution of remaining oil depends on the injection-production position and the connectivity mode of the fracture-karst. The remaining oil mainly distributes in bypass fault-karst of non-dominant channel，small arch and the bottom of fault-karst.