This paper aims to explore how to innovate and optimize the public physical education teaching system in colleges to promote the concrete implementation and practice of the national fitness policy in higher education institutions. Currently, public physical education in colleges faces issues such as a single teaching model, low student participation, and insufficient cultivation of core competencies. To address these problems, this research proposes the “Cubic Core” teaching system, constructing a multidimensional, three-dimensional teaching model for college public physical education. This system integrates a five-in-one model of “learning, practicing, testing, competing, and teaching” as its length, establishes a connection mechanism of “home, school, and community” as its breadth, and incorporates a progressive structure for cultivating core physical literacy as its height. The implementation of this system aims to enhance students’ core physical literacy, stimulate their enthusiasm for participating in physical activities, and promote the collaborative support of home, school, and community. This research hopes to provide new ideas and methods for public physical education in colleges, contributing to the realization of the goal of building a strong sports nation.