In recent years, the demand for children’s activities has been increasing, and the children’s consumer market has expanded annually. A large number of urban commercial spaces for children’s activity that meet the needs of children’s activities have been built in Chinese cities. This paper analyzed the distribution of these spaces in Changchun City, divided children’s activity space into five categories, analyzed the distribution and spatial differentiation using ArcGIS tools, and discussed the formation mechanism of the spatial pattern of children’s activity space. The results show that: (a) The spatial agglomeration of children’s activity places in Changchun was remarkable and formed a multicore spatial pattern of three municipal and six district-level centers. (b) Different varieties of children’s activity places showed significant spatial differences with “center–periphery” and spatial distribution patterns and each block unit had specialized characteristics. (c) The diversification and social demand for children’s activities, children’s consumption (a new growth factor for the modern service industry), market competition for rent, coupling relationship with urban functional areas, traffic convenience and accessibility, and changes of children’s activity behavior patterns and preferences were the main factors that influence commercial children’s activity space in Changchun. (d) The inequitable spatial distribution of children’s activities, the poor accessibility of children’s activity places, the lack of outdoor places and natural elements, the excessive concentration of children’s activities, and the lack of reasonable guidance of children’s commercial activity places in the city pose challenges for daily activities of urban children. Based on these results, this paper put forward some constructive policy suggestions, such as the planned addition of children’s public places and children’s outdoor places, enriched green and natural elements of children’s places, the construction of children’s activities facilities in residential areas, and the addition of children’s activity facilities in the compulsory standards for urban construction.