Abstract: [Significance] Fault-karst reservoir is widely developed in most basins in China, and its resources are huge, which has become a new hot topic in the field of geography. However, due to the deep burial and difficult exploration of fault-karst reservoir, and it is urgent to form a consensus understanding of trap division, formation mechanism and development control factors. [Progress and Conclusions] Based on literature research, this paper deeply discusses the formation mechanism of fault-karst reservoir. Fault-karst reservoir is a kind of fracture-vuggy reservoir formed in carbonate strata by karstification under the influence of multi-stage tectonic activities. Firstly, the basic concept of Fault-karst reservoir is reviewed. It is pointed out that fault-karst reservoir has the characteristics of deep burial, strong heterogeneity and large difference of fluid properties, and the important role of strike-slip fault in hydrocarbon accumulation and migration is emphasized. Based on the analysis of geological data in Shunbei area and other areas of Tarim Basin, this paper reveals the trap types, formation mechanisms and reservoir-controlling factors of fault-karst reservoir. It is concluded that the segmentation of strike-slip faults, the activity of solution fluid and the timely emplacement of hydrocarbons are crucial to the development of fault-karst reservoir. What's more, the roles of atmospheric fresh water, hydrothermal fluids and hydrocarbon fluids in reservoir reconstruction are also discussed, and how they jointly affect the formation and distribution of Fault-karst reservoir. At last, the paper summarizes the reservoir-forming models of fault-karst reservoir. [Prospects] The discovery and understanding of fault-karst oil reservoir have opened up a new field and direction of oil and gas exploration.