Nasal congestion at night may be caused by physiological factors, adenoid hypertrophy and allergic factors. 1. Physiological factors: at night when sleeping indoor temperature is relatively low, the nasal cavity by the cold air stimulation, easy to make the nasal mucosa congestion and edema, there will be nasal congestion, in the daytime, the temperature increases after the gradual improvement. 2. Adenoid hypertrophy: some patients with adenoid hypertrophy will also experience nasal congestion at night, which may be accompanied by night snoring, restless sleep, open-mouth breathing, tinnitus, hearing impairment and other manifestations. 3. Allergic factors: the presence of dust mites on bedsheets and bedding may cause allergic reactions in the local nasal cavity during sleep, which may lead to nasal congestion, accompanied by sneezing, runny nose and other symptoms. Nasal congestion at night can also be caused by other reasons, it is recommended to go to the hospital for a systematic examination to clarify the diagnosis.