To study the detection effect of the high-density electrical resistivity method on chromium-contaminated sites, the resistivity model of chromium pollution was established. The finite difference method and the least square method were used to perform forward and inversion to analyze the resistivity characteristics of chromium pollution. Then, the detection effect of different pollution concentrations under different device types is obtained. Subsequently, the high-density electrical resistivity method was carried out on a chromium contaminated site in Hebei, and the distribution of the underground pollution plume was obtained. The detection results were verified by drilling. Theoretical analysis and actual detection results show that the resistivity of underground soil polluted by chromium is relatively low, which is significantly different from that of uncontaminated soil. With the weakening of pollution degree, the identification ability of high-density electrical resistivity also decreases and the detection effects of different device types are also different. The above research results provide an important theoretical and practical basis for the site investigation of the same type of heavy metal pollution in the future.