When newborns reach two to three months of age, they gradually learn two actions as their brains develop: one is to stare at their hands with their eyes, and the other is to suck their fingers. For them, finger sucking is a form of learning and play. The progression from awkwardly sucking on the whole hand to deftly sucking on a particular finger indicates that infants are much more capable of governing their own behavior. The finger-sucking action prompts the infant’s hand and eye to act in a coordinated manner, laying a solid foundation for learning to grasp toys accurately around 5 months of age. In addition, infants in this period learn about the outside world mainly through their mouths. Infants think that their hands are also something outside, so they always like to stick it in their mouths and suck on it to perceive it. Usually, with the rapid development of infants’ movements, they gradually learn to sit, crawl, stand, etc. freely, and their finger movements become more and more refined, and when they grow to be able to play with toys alone, the phenomenon of children sucking their fingers will naturally be greatly reduced. In addition, careful parents can find that children are usually very quiet when they suck their fingers and do not cry or make a fuss. In fact, sometimes babies suck their fingers to stabilize themselves, which means that finger sucking plays an important role in their psychological development. Therefore, parents do not need to be anxious about finger sucking and do not need to forcefully stop it. If the child’s behavior is too frequent, parents can often stroke and wiggle the child’s little hand to distract him or her from finger sucking. What parents need to do is to keep the baby’s hands clean and keep the area around the baby’s mouth and lips clean and dry so that eczema does not occur. However, if the child is still sucking his or her fingers frequently after the age of one or even at the age of three or four, it can be considered as a bad behavior and parents need to carefully understand the reasons for its formation and correct it patiently.