The wave-particle duality relate to the space-time property of matter byPlanck constant. The ï¬ne structure constant is linked to the double-slit and the uncer-tainty principle in Quantum Mechanics. Compton scattering and interference of double-slit is established by the cross-linked angle T01 = Tc cos(Î¸2), and vice versa. The single-slit direction is described by Sinc-function which could combine the classical diï¬€raction and quantum interference eï¬€ect in the same experiment. This space-time model explain the experimental mystery of the double-slit.