The widespread presence of humic acids (HAs) and chromium (Cr) in aquatic systems and drinking water sources is a serious threat to the environment and human being, which attracts great concerns from the protection of public health.^1,2 However, no attempts on the potential interaction and simultaneous removal of these two types of contaminants have been made. Here, an electro-Fenton process was reported for the effective and simultaneous removal of HAs and Cr(VI), where H₂O₂ was in-situ produced from the electro-generated H₂ and O₂ by the presence of Pd/Fe₃O₄ nanocatalysts and Fe(II) was provided from the support. The effects of solution pH, applied current, Pd loading, and initial concentrations of HAs and Pd/Fe₃O₄ on the removal efficiency of HAs and Cr(VI) were carefully investigated. Under the optimized electrolysis conditions (pH 3.0, 40 mA, 5.0 wt % Pd, 100 mg•L-1 HAs and 5.0 g•L^-1 Pd/Fe₃O₄), HAs were effectively mineralized, as revealed by a total organic carbon removal efficiency of 90%, and Cr(VI) was completely reduced accompanying with 90% total Cr removal. The HAs degradation driven by the contribution of anodic oxidation was found to be important but not dominant, whereas electro-Fenton process played a fundamental role for the mineralization of HAs. The reduction of Cr(VI) was primarily attributed to the contributions from Pd/Fe₃O₄ and atomic hydrogen on the Pd catalyst surface as well as the cathodic reduction. In a similar manner, a good recycle of Fe³⁺ to Fe²⁺ was accelerated. Moreover, most chromium was removed by the deposit of chromite from the solution, which is the most common and stable mineral of chromium in the environment. Importantly, the energy consumption of this electro-Fenton process for HAs degradation was almost 2 orders of magnitude lower than those of reported electrochemical oxidation. The Pd/Fe₃O₄ nanocatalysts showed excellent removal performances for HAs and Cr(VI) after eight times repeated treatment. This work reports a cost-effective methodology for simultaneous removal of HAs and Cr(VI) and provides a new insight for efficient elimination of complex contaminants.