Large cholesterol granuloma cyst has been rarely reported in patients with previous ear surgery history. Large cholesterol granuloma cyst usually mimicked brain herniation in open cavity mastoidectomy cases, but filled with mastoid cavity and ear canal or caused postauricular swelling in closed cavity cases, and granulomatous tissue filled the bone around the cyst. Recently we experienced a case of cholesterol granuloma cyst in a 35 years old male patient during the revision ear surgery, and report this case with review of literatures.