Reninoma is a rare renal secretory tumor，prevalent in the young population. This disease is mostly surgically resected，and the use of microwave ablation to treat reninoma in children is scarce. A case of reninoma in a child was reported in this paper. The patient presented with refractory hypertension，hypokalemia，hyperreninemia and hyperaldosteronemia. Enhanced CT and contrast-enhanced ultrasound showed mass in the lower pole of the right kidney，which was considered as reninoma and microwave ablation was performed. The renin concentration decreased to 68.42 pg/ml at 4 hours after surgery. After 1 year of postoperative follow-up，there was no recurrence of hypertension and hypokalemia，and no signs of tumor recurrence were seen on repeated ultrasound examinations.

Reninoma is a rare renal secretory tumor，prevalent in the young population. This disease is mostly surgically resected，and the use of microwave ablation to treat reninoma in children is scarce. A case of reninoma in a child was reported in this paper. The patient presented with refractory hypertension，hypokalemia，hyperreninemia and hyperaldosteronemia. Enhanced CT and contrast-enhanced ultrasound showed mass in the lower pole of the right kidney，which was considered as reninoma and microwave ablation was performed. The renin concentration decreased to 68.42 pg/ml at 4 hours after surgery. After 1 year of postoperative follow-up，there was no recurrence of hypertension and hypokalemia，and no signs of tumor recurrence were seen on repeated ultrasound examinations.