Generally speaking, infants can turn over skillfully at 7 months old. In addition to turning over, infants’ balance and gross and fine movements are different at different times. 1. Balance and major movements (1) Rolling over: at 7 months of age, infants can consciously roll over from prone to supine position and then from supine to prone position. (2) Head lifting: As a newborn, the head can be lifted for 1~2 seconds in the prone position. The head lifting is more stable at 3 months, and by 4 months, the head lifting is already very stable. (3) Sitting: At 6 months, the baby can sit alone for a while, at 7 months, the baby can sit alone for a long time, and at 8 months, the baby can sit steadily. (4) Crawling: At 3 to 4 months, you should start training your infant to crawl, and by 8 to 9 months, your infant will crawl forward with both upper limbs. (2) Fine motor: left and right grip reflexes disappear around 3 months, exploratory movements such as pinching can occur at 6~7 months, and at 9~10 months, the infant can use the thumb and forefinger to pick up objects. 7 months when the baby will roll over, but also need to pay attention to other aspects of the motor situation, if the development is delayed, etc. need to go to the hospital in a timely manner, with the help of a professional doctor to take appropriate measures to deal with.