A 63-year-old male was diagnosed with type 2 diabetes, diabetic nephropathy, renal hypertension, and renal anemia (Hb 72 g/L). Oral roxadustat 100 mg TIW and oral iron 200 mg QD were given to treat renal anemia. The peritoneal dialysis was adequate. But the effect of hemoglobin elevation was not satisfactory. Despite the patient weighing 58 KG, the roxadustat was administered at a dose of 120 mg of TIW, and oral iron supplementation was continued. Due to almost no further increase in hemoglobin, intravenous iron supplementation was given in the third month. After 4 weeks with a total of 800 mg iron supplementation, the Hb concentration reached 96 g/L. Roxadustat was further reduced to 70 mg TIW along with oral iron, the Hb concentration in the 8th month was 114 g/L. This case showed that merely overdosing roxadustat cannot improve renal anemia. Although oral iron supplementation suffices for most patients, if ferritin and hemoglobin do not obviously improve in patients receiving oral iron supplementation, intravenous iron supplementation is needed.