The work aims to construct outdoor hidden play space and facilities that cater to the developmental demand of children between the ages of 4 and 7, so as to minimize the need for adult supervision and regulation during children's playtime, allow children to engage in free and self-directed play and support them in developing a strong sense of self-identity, fostering independence and self-assurance, and nurturing their emotional intelligence and social interaction abilities. The psychological and behavioral characteristics of children's play behavior at the age of 4-7 were analyzed, and the effect of play space and facilities on children's play behavior and psychological characteristics at the age of 4-7 was explored, so as to get the specific requirements of children's developmental demand for outdoor play space and facilities. Then, in combination with children's self-development and independent play, the key points of designing children's outdoor hidden play space and facilities were analyzed. Finally, from the three phases of determining the theme, designing the scheme and demonstrating the effects of children's play space and facilities, the outdoor hidden play space and facilities which could satisfy the developmental demand of children at the age of 4-7 were constructed. Three distinct types of outdoor hidden spaces were constructed, including a hidden space designed to facilitate deep participation among children, a poetic hidden space highlighting the contrast between nature and society, and a symbolic division labyrinth catering to children's desire for independent play. Additionally, these hidden spaces incorporated engaging and manipulative amusement facilities in line with the specific attributes of each space. The design considerations for these facilities encompassed their shapes, materials, and colors, all of which aimed to stimulate children's imaginations, enhance their enthusiasm for play, and foster their curiosity for exploration. The design scheme of play spaces and facilities aimed at promoting the development of children aged 4 to 7 is constructed, which is conductive to the enhancement of children's physical and mental well-being and offers novel design concepts and guidance for the advancement of the play industry catering to children within this age group.