Abstract: Infant toys are the most important partners in their growth. Nowadays, most infant toys design tend to meet the market demand, and the demand factors of babies themselves gradually fade away. Therefore, it is particularly important to study the design of toys based on babies' own needs. Based on the principle of behavior-oriented design, the paper studied the hand development and fine movement of infants are studied at each stage, and summarized the developmental needs of infants at different growth stages. According to the principle of baby's hand behavior-oriented design, it is concluded that infant toys design should pay attention to baby's thumb development, five-finger-tip coordination and hand-eye coordination, so as to promote baby's hand and intelligence development according to the research of product design elements, and provide help for the design of infant toys in the future.