Cochlear implantation (CI) is the most effective solution for patients with severe-to-profound sensorineural hearing loss, especially in children. However, a major postoperative complication, known as chronic suppurative otitis media (CSOM), poses challenges for both doctors and families of the patients, which can affect post-CI hearing outcomes. We present the case of post-CI CSOM in a 15-year-old girl. She had been utilizing a unilateral cochlear implant for 7 years and had been experiencing intermittent earache and discharge in her only audible ear for the past 15 months. After antibiotic treatment failed to resolve her symptoms, we opted for a tympanomastoidectomy, and removed the receiver-stimulator package while keeping the electrode inside her cochlea. Simultaneously, we inserted an irrigation and drainage tube into the mastoid and middle ear space to discharge the exudate and control infection by applying topical antibiotics. The patient’s ear discharge had resolved within 1 month, and her tympanic membrane healed naturally. Our successful experience shows that antibiotic irrigation and draining have effectively controlled infection and accelerated wound healing in this patient with post-CI CSOM, and it further prompted the patient to undergo bilateral CI 9 months later.