Babies are able to hold their heads up at one month of age, but they are not able to hold their heads up steadily until 2-3 months of age. Babies can hold their heads upright for 3-5 seconds in the sitting position at one month, barely tilt their heads in the sitting position at 2-3 months, and hold their heads steadily at 4-6 months. Babies are able to lie prone a few days after birth, but the ability to raise their heads after lying prone does not occur until the baby is two months old. When the child is three months old, he or she can form a curvature of the spine and can lift the head on his or her own, and when the baby is able to sit alone at 6-7 months, he or she forms a chest curve. The waist curve is formed when the baby is able to run and walk around one year old. How to judge the baby can lift the head, the baby does not need other people’s support when holding it vertically, and the head will not shake or the baby can support the body when lying prone, lift the head to stay for a while, and can look to the left and right and move the head freely. Or the baby can raise his head, hold the baby’s hand to lift the baby up, so that the baby’s back and the ground between about 45 degrees, then the baby’s head can be raised steadily, and the body into a straight line.