In order to study the resistivity characteristics and mechanism of solidified loess mixed with CaOmodified red mud, the resistivity of the samples with different CaO and red mud content and curing age was tested. In addition, XRD, SEM, EDS, porosity and pore-throat distribution of these samples under different conditions were tested to analyze the mechanism of resistivity change. The results show that the resistivity decreases with the increase of CaO and red mud. Compared with cement solidified soil, the types and concentrations of conductive ions in pore water of the cement solidified soil modified by CaO and red mud increase, which leads to the increase of conductivity of pore water. With the increase of curing age, the resistivity overall presents a trend of logarithmic increase. Due to the excessive CaO unreacted in the solidified soil, the conductive ions still exist in pore water. Therefore, the decrease of pore water conductivity is limited when the curing age is longer than 28 days. Moreover, Due to the increase of the porosity and pore-throat distribution of the cement solidified soil modified by CaO and red mud, the internal disconnecting paths increase and the conduction paths reduce, which increases the resistivity with the increase of curing age.