Babies always cry at night may be caused by environmental factors, may also be rickets, colic, etc., should be timely consultation to identify the cause of the disease. 1. Environmental factors: for example, the baby’s environmental temperature is too high or too low, cover the bedding is too thin or too thick, wrapped too tightly, resulting in the child uncomfortable caused by crying. Secondly, the environment in which the child sleeps is too noisy, which can also cause the child to cry. 2. Rickets: the baby was born two weeks after the start of vitamin D supplementation, if the child supplementation is not timely or sun exposure is relatively small, there may be rickets manifestations, such as restless night sleep, easy to startle, excessive sweating, occipital baldness and so on. 3. Colic: Babies are prone to colic before three months, which is related to children’s weaker gastrointestinal function and poor digestion. In addition to the above factors, do not rule out other factors caused by, it is recommended to take the child to the hospital to check the cause of the disease, according to the condition to take targeted treatment to treat.