Humans are distinguished from other animals by their flexible hands, which give them the ability to make tools and use them. This is an evolutionary and uniquely human function, i.e., the genetic basis that determines that human hands are different from those of other animals. A monkey can open a bottle cap with his hands and peel and eat a banana; but no matter how much he is taught he cannot learn to write, button, type, etc.; he cannot make new things. The complex structural basis of the human nervous system is the basis for the ability of the hand to go from being unable to do anything to being able to perform fine motor operations. In addition to the brain, a complete structural base of peripheral nerves and muscle joints is necessary. The development of the brain is not complete in the newborn child, and most of it is not completed until 2 to 3 years of age after birth. As the brain continues to develop after birth, the functions of the hands gradually emerge and are refined. When a newborn baby holds his hands tightly, the adult’s fingers are placed in the baby’s hands and he will grasp them tightly, which is the original hand function, not controlled by the brain. 4~5 months old baby will actively reach out to grasp the objects in front of him when he sees them, which is the earliest functional hand activity; by 9~10 months old, he will not only take the things he wants, but also turn the objects in his hands over and over. Play with, watch, throw away, pick up …… will extend the index finger to insert the fingertip into the hole; 1.5 to 2 years old when the hand becomes more flexible, will turn the book, will open the bottle lid, their own clothes, socks, their own water cups to drink water, etc., and later will do more delicate operations. The innate developmental basis plays a fundamental role in the development of hand function and the level of hand manipulation. It is also influenced by environmental and other factors. For example, socio-cultural factors. The role of expectations will make the child from an early age to be more trained, hand manipulation ability will be stronger; visual impairment obviously affects the development of the hand, which affects the development of cognitive function, commonly known as because of the inaccuracy of seeing clearly, inaccurate, resulting in distortion of the reflection of objective things in the brain and cognitive inaccuracy and deficiencies. The feedback of sensory information is the impact of sensory aspects. The hand grasps the object, receives the sensory information and transmits it to the brain, which analyzes and interprets the sensory information and then makes a judgment. The hand sensory information can tell you hot, cool, hard, soft, light, heavy, large, small and so on. The brain synthesizes a variety of information and then makes a judgment. Therefore, abnormal sensory perception affects hand development, such as upper limb nerve damage in children will not clearly obtain sensory information. However, extrinsic factors do not affect basic functional development. Various known and unknowable causes of delayed and impaired brain development can affect the development of hand function and other aspects of pediatric function to varying degrees. Delayed development and abnormal hand manipulation are manifested in infancy and early childhood and can be clumsy by school age. This affects learning and future life and work to varying degrees. Whether the development is normal or abnormal, planned training of children’s hands from an early age to provide them with more opportunities for appropriate manipulation has obvious benefits for the improvement of hand function and hand-related cognitive functions and hand-eye coordination. For normal children hand function will be better, for hyperactive, poor attention can improve concentration, for slow development can catch up, and even for children with cerebral palsy strabismus can correct strabismus …… Why is the ability to manipulate the hands of children related to cognition? To give an example, when a wooden sphere is in front of his eyes, he tries to reach out and grab it for the first time, if the ball is big and he can’t grab it, he will also try to grab it and still can’t grab it, if he has the ability to collaborate with two heads, he will try to use both hands to get it. Slowly, after many repetitions, he has a basis for judging the size, and later he will use both hands directly when he sees a large object or sphere, and will not waste time trying with one hand first. Each operation has corresponding information input into the brain, and the combination of many information provides a rich accumulation of material for future application to improve cognitive ability. As long as it is safe and age-appropriate, anything can be used as a toy, and any kind of toy is beneficial to the child. Colorful and age-appropriate toys, tools, games (play house, folk games, with or without technology) and so on are very beneficial to children’s brain, hand development and other development, not necessarily need to spend money to play. Extensive practice promotes the development of sensory, perceptual and kinesthetic senses, the improvement of observation, concentration, and strong hand-eye coordination, laying a rich and solid foundation for the good development of cognitive abilities. Through observation and analysis of children’s activities, occupational therapists can assess the development of hand function and all related aspects of children’s development, and use this as a basis for designing games and homework activities, making plans appropriate to children’s level and potential, and implementing them, which can have a very positive effect on promoting and improving children’s development. Parents should learn and understand about the development of their children, learn how to detect the developmental characteristics of their children and learn how to play with their children, which is necessary for parenting and family education so that the children are not only physically strong but also mentally developed.