We present a case report of a 58-year-old male on peritoneal dialysis with a history of diabetic nephropathy. The patient was admitted to the hospital due to with extremely high hemoglobin concentration, with a hemoglobin level of 212 g/L. To explore the cause of anemia, bone marrow puncture was performed. The patient’s bone marrow showed that granuloid and erythroid were not significantly abnormal. Roxadustat, a hypoxia-inducing factor prolyl hydroxylase inhibitor, can improve renal anemia by promoting EPO expression and improving iron metabolism. In this case, roxadustat demonstrated efficacy in improving both the anemia condition and iron metabolism of the patient. However, it also serves as a reminder of the critical importance of routinely monitoring hemoglobin levels and making appropriate dosage adjustments during the course of roxadustat treatment. It is essential to avert potential adverse reactions that may arise from an abnormal increase in hemoglobin concentration.