One and a half year old children crying at night may be physiological factors, but also may be related to pathological diseases, such as skin diseases, rickets and so on. 1. Physiological factors: such as overheating, too cold, hungry, want to urinate and defecate and other reasons lead to children crying at night. It is also possible that the child suddenly change the environment, not accustomed to not adapt. Or dreaming at night causes children to cry at night. 2. Pathological factors: children with skin diseases, pinworms, hernia, rickets and other causes of physical discomfort or itching, will also cause children to cry at night. This kind of crying is more intense, not good to appease. A one and a half year old child crying at night may also have other reasons, it is recommended to go to the hospital in time to improve the examination to clarify the cause of the disease, to give targeted treatment or treatment.