Abstract The fine-structure constant is the core dimensionless coupling constant of quantum electrodynamics. Traditional physics defines it as an absolutely fixed fundamental cosmic constant, which cannot explain the coupling deviation under spacetime evolution and topological deformation. This paper constructs the Super Computing Primitive Analytical Model, introduces modulus space transition projection operators and nonlinear superposition rules of vortex manifolds, and establishes the cross-modulus analytical general formula and dynamic spacetime correction equation of the fine-structure constant. The model breaks the traditional solidified cognition of constant invariance and proves that the fine-structure constant is a dynamic field quantity dependent on spacetime phase and time. It is nonlinearly superposed by the primitive reference value and the time correction term of spacetime phase gradient, and can describe the dynamic drift law of electromagnetic coupling intensity under microscopic spacetime optical deformation and topological deformation. This paper completes model self-consistency verification, physical mechanism interpretation and theoretical system construction, providing a brand-new theoretical framework for the dynamic evolution of fundamental physical constants and the research of spacetime primitive structure.