Abstract: Hydrocarbon reservoir of 3rd member of Funing formation in Taixing oilfield, Qintong depression of Subei basin is the target interval of this research. Based on petroleum geology and well logging, with the information of core samples tested, this paper makes an analysis on its major and minor factors which might lead to low resistivity in the area. The results show that there are four major controlling factors:fine grain size of rock skeleton, the content, type and existential characteristic of clay mineral, complex pore throat texture and reservoir wettability; two minor factors are: rich abundance of conductive metal mineral in the target interval and high reservoir water salinity.