This study constructs a gravitational-entropy dynamic equilibrium model by coupling general relativity and thermodynamics, demonstrating that cosmic expansion can be driven by the natural competition between gravitational potential and entropy increase—without introducing dark energy. The model derives a Hubble constant of 67.3 km/s/Mpc, which is in high agreement with observations from the Planck satellite [7]. It also defines two critical scales: a global scale (513 Mpc) and a local scale (160 Mpc), matching the observational characteristics of the Coma Supercluster [9]and Laniakea Supercluster [8], respectively. The results show that the dark energy hypothesis is redundant at both mathematical and physical levels [10], and cosmic evolution can be uniformly described by fundamental physical laws, consistent with Occam’s Razor principle.