We described that a 55-year-old man was referred to our hospital for a 15-day history of onset acute kidney injury. An unusual hematoma in posterior abdominal wall following renal biopsy was revealed due to the injury of abdominal wall vascular, which was initially misdiagnosed as renal hemorrhage. After conservative treatment, the patient’s symptoms slowly improved 1 week later and the hematoma was not increasing in size. Conservative treatment for abdominal wall hematoma is allowed if the patient’s condition is stable. Invasive approaches or surgery will be effective in controlling active bleeding.