Abstract: In order to shorten the high pressure oxidation leaching time of chromite in a high concentration of sodium hydroxide aqueous solution, this paper pretreats chromite ore by microwave roasting. The effect of microwave roasting on the structure and leaching of chromite is investigated. The results show that, after microwave roasting at 800 ℃, a large number of cracks appear on the surface of chromite, the structure is no longer dense, and the particle size of the chromite greatly reduces. Under the reaction conditions of a temperature of 240 ℃, O2 partial pressure of 2.2 MPa, NaOH-to-ore ratio of 4∶1, stirring speed of 700 r/min and NaOH concentration of 60 wt.%, the chromium leaching rate reaches over 97.81% after a reaction time of 120 min. The results show that using microwave roasted chromite for pressure oxidation leaching can greatly improve chromium leaching efficiency.