The invention discloses a method for treating wastewater generated in the production process of iron oxide pigment. The method comprises the following steps of: 1) adjusting pH value of the wastewater to recover iron oxide pigment from the wastewater; 2) using organic wastewater as an organic carbon source; and 3) treating the wastewater generated the production process of the iron oxide pigment by using an anaerobic-anoxic-aerobic biochemical system. The method for treating the wastewater is simple and easy. The iron oxide pigment is recovered from the wastewater, so that resources are utilized reasonably, and secondary pollution caused by precipitate treatment can be reduced; the organic wastewater used as the carbon source replaces an organic reagent, wastes are treated with processes of wastes against one another, the wastewater is recycled, and the method has good economic and social benefits; and the anaerobic-anoxic-aerobic biochemical treatment system is introduced into iron oxide pigment wastewater industry first, and an obvious effect is achieved. After treatment, the content of ammonia nitrogen in the ferric oxide wastewater is less than 5mg/L, the chemical oxygen demand (COD) is less than 100mg/L, and the first-class discharge standard of the national 'integrated wastewater discharge standard' is met.