The most common cause of foul-smelling nasal discharge is fungal sinusitis. Fungal sinusitis is a sinus symptom that results from the inhalation of fungal pathogens in the nasal cavity, after the patient’s immunity and resistance have been reduced. Fungal sinusitis generally progresses slowly, is seen in women, and has a limited unilateral sinus onset, commonly in the maxillary sinus, resulting in nasal congestion, runny nose, blood in the nose, headache, facial swelling and pain, and a lot of cheese like white lumps in the nose, and occasionally green jelly-like material, with a foul odor in the nose. During the examination, congestion and edema of the turbinate mucosa can be found, and polypoid changes can be seen in the middle turbinate, and a large amount of cheese-like masses can be found at the opening of the maxillary sinus in the middle nasal tract. If the diagnosis of fungal sinusitis is confirmed, the patient needs to undergo endoscopic radical sinus surgery with postoperative antifungal medication and can be discharged from the hospital in about a week.