The main reasons for 80-day-old babies to cry at night include fright, environmental discomfort, diaper discomfort, and illness. Improvement methods include soothing emotions, improving the environment, changing diapers, and treating diseases. 1. Frightened: If the baby is strongly stimulated or sees something exciting, the baby will cry at night, parents should promptly calm the baby’s emotions and give the baby a sufficient sense of security. 2. Environmental discomfort: because the baby’s thermoregulatory center is not well developed, if the sleeping environment is too cold or too hot, it will cause the baby to have a strong sense of discomfort, then you should actively adjust the indoor temperature to avoid too hot or too cold. 3. Diaper discomfort: baby urination and defecation parents did not change in time, resulting in baby discomfort, parents should pay attention to observe the baby, timely change of diapers. 4. Disease: babies cry at night when they have fever or abdominal pain and bloating, parents should exclude other possible factors, should immediately consult a doctor and timely treatment of the symptoms. There are physiological and pathological reasons for babies to cry at night. Parents should observe the state of their babies in time and consult the doctor immediately if there is any discomfort.