Modern physics faces a profound theoretical chasm when bridging microscopic quantum scales and macroscopic cosmological scales, most notably manifested in the hierarchy problem and the dark matter hypothesis. Based on thefirst principles of spatial fluid dynamics, this paper proposes a scale-dependent spacetime topological phase transition model. The model postulates that the fundamental geometric topology of spacetime is a cylindrical spiral manifold (S^1 x R). When the particle number reaches the stellar mass scale (N ~ 10^57 ), the rotational degrees of freedom of microscopic spirals cancel out due to statistical decoherence (governed by the central limit theorem). Consequently, the spatial topology collapses into a purely divergent, isotropic Gaussian sphere (S^2), which manifests macroscopically as classical Newtonian gravity. Starting from the first-principle axiomomega*r = c, this paper rigorously derives the pure geometric expression for the universal gravitational constant G = C^3r^2_0/h-bar, proving that G is intrinsically a topological constant determined by the critical radius of the topological phase transition. Furthermore, at galactic and cosmic web scales (N ~ 10^68 - 10^80), stars act as new fundamental units, and their collective spin generates macroscopicspacetime torsion within the framework of Einstein-Cartan theory. This torsion drives spontaneous symmetry breaking, thereby reconstructing a macroscopic cylindrical spiral structure. Supported by numerical integration and recent astronomical observations (e.g., cosmic filament spin, CMB anomalies), this model provides a computable and falsifiable pure geometric pathway toward unifying quantummechanics, general relativity, and dark-matter-free cosmology.