Obtaining the hydraulic conductivity characteristics of widely distributed fault zones is the key to evaluating potential underground nuclear waste repositories. However, there are currently certain limitations on the methods for such data collection. In this study, electrical resistivity tomography (ERT) was combined with pumping test data to obtain the distribution of hydraulic conductivity in fault zones. The hydraulic conductivity of the aquifer was obtained through 30 pumping tests in seven pumping wells, and the results were then fitted with the aquifer resistivity obtained by the ERT at the corresponding positions to establish the relationship between the resistivity and the hydraulic conductivity, according to which the hydraulic conductivity characteristics of the fault zone can be obtained using the resistivity value. The results show that for the sandstone area with a small hydraulic conductivity, the result of exponential fitting is more accurate (R2 = 0.97) than that of linear fitting and power fitting. The hydraulic conductivity calculated based on the established R-K relationship has an error of less than 10.50% compared with that measured by the pumping tests, and the Nash-Sutcliffe efficiency coefficient is 0.96. Furthermore, the spatial distribution of the hydraulic conductivity of the fault zone in the study area was calculated based on this relationship, providing a basis for more accurate and low-cost descriptions of groundwater and solutions transport in the fault zone.