Bases on the data of geology, drilling, logging and geochemistry, the formation conditions and distribution rules of tight oil reservoir in Fuyu oil layer of Sanzhap area were systematically analyzed. The results show that the study area has four advantages for tight oil accumulation. The crude oil is of good quality and strong fluidity, and the formation condition of the dense oil is superior. High quality hydrocarbon source rocks with wide coverage and large area distribution are close to the tight reservoirs, which provide sufficient oil source for the formation of tight oil reservoir. The compact reservoirs with wide area distribution provide effective reservoir space for the formation of compact oil reservoirs. The formation overpressure matches with the oil source fault, which provides sufficient power for the oil migration. At last, it is pointed out that the tight oil in Fuyu oil reservoir in Sanzhao area has the characteristics of large area (quasi) continuous distribution, strong oil heterogeneity. The channel sand body controls the local sweet area of the tight oil.