Abstract: In this study, copper slag was treated by carbothermal reduction to prepare of porous silicate supported micro-nano ZVI (micro-nano iron). The effects of roasting conditions and degradation conditions on the performance of micro-nano iron for removing Cr(VI) from wastewater were investigated, and the reaction mechanisms are studied. Results showed that the micro-nano iron prepared under the conditions of calcination temperature of 1 150 ℃, calcination time of 40 min, and coal dosage of 25% presented the best performance for removing Cr(VI). Scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) showed that copper slag forms porous structure after reduction roasting, and a large number of nano-sized to micro-sized ZVI particles were generated on the surface of silicate matrix hole. The Cr(VI) removal process was enhanced by increasing the micro-nano iron dosage and solution temperature, and decreasing the initial pH of the solution. The mechanism analysis shows that the micro-nano iron and Cr(VI) have undergone an oxidation-reduction reaction, and Cr(VI)was reduced to Cr(Ⅲ)and mineralized into chromite.