The resistivity test technology has advantages such as convenient, rapid and nondestructive when evaluating mechanical properties of solidified heavy metal contaminated soil. In this study, the combined resistivity-unconfined compression test method was carried out to investigate strength and electrical properties of solid waste solidified contaminated soil. The results showed that the red mud-carbide slag-phosphogypsum solidified contaminated soil has higher strength, in which, both peak stress and failure strain increase with the increase of curing age. The solidified soil also exhibited a stable change law between its strength and resistivity. There was a stable variation law between strength and resistivity of the solidified soil, which showed a good linear relationship. A power function relationship between strain and dynamic resistivity was also observed through stress-strain dynamic resistivity curve analysis. An electrical characterization model of mechanics is established by replacing the strain with dynamic resistivity in the strain softening model. Coincidence degree of the model is high based on comparison and verification indicating that the dynamic resistivity change value has high reliability to represent the stress and deformation performances of the solidified soil.