Against the backdrop of rising academic attention to nature-based education within early childhood education circles, the localized indigenous curriculum Germinating Four Seasons developed by Huazhong Agricultural University Kindergarten incorporates nature-based play as its core teaching module, furnishing tangible practical carriers for fostering the comprehensive social competence of senior preschool children. Targeting senior preschool learners, this paper integrates Jean Piaget’s Cognitive Development Theory, Lev Vygotsky’s Sociocultural Theory and John Dewey’s “Learning by Doing” Theory. Drawing on systematic literature collation and on-site practical exploration, the paper first delineates the definitive connotation of nature-based play, then conducts an in-depth dissection of the ideal developmental benchmarks, realistic predicaments and underlying root causes of senior preschool children’s three-dimensional social competence encompassing interpersonal communication, awareness of rules and peer collaboration. Furthermore, this study puts forward targeted, operable practical strategies to cultivate children’s social competence via nature-based play from three interrelated dimensions: seasonal-themed natural scene construction, child-centered rule formulation, and the design of collaborative challenging tasks. The research can deliver systematic theoretical references and frontline instructional guidance for the design and implementation of nature-based curricula as well as the targeted cultivation of preschool children’s social competence.