This article presents the development of a mechanical stretch α-cyclodextrin pseudopolyrotaxane elastomer with reversible phosphorescence behavior. The elastomer is created by threading naphthalene-functionalized polyethylene glycol (NPEG) chains into α-cyclodextrin (α-CD) cavities to form a pseudopolyrotaxane (NPR). This structure not only enhances the phosphorescence of the naphthalene group through the confinement effect of α-CD but also provides interfacial hydrogen bonding with waterborne polyurethane (WPU) chains, resulting in improved mechanical properties. The elastomer exhibits excellent room temperature phosphorescence (RTP) that remains stable in water, acid, alkali, and organic solvents, even at high temperatures of 160 °C. Notably, the phosphorescence intensity increases threefold under 200% strain, demonstrating reversible mechanical responsiveness. This behavior is attributed to strain-induced microstructural changes that suppress non-radiative transitions and vibrations of NPR. The study highlights the potential of this supramolecular elastomer in applications such as information security and encryption. The material's stability and tunable phosphorescence make it a promising candidate for advanced luminescent materials with mechanical responsiveness.This article presents the development of a mechanical stretch α-cyclodextrin pseudopolyrotaxane elastomer with reversible phosphorescence behavior. The elastomer is created by threading naphthalene-functionalized polyethylene glycol (NPEG) chains into α-cyclodextrin (α-CD) cavities to form a pseudopolyrotaxane (NPR). This structure not only enhances the phosphorescence of the naphthalene group through the confinement effect of α-CD but also provides interfacial hydrogen bonding with waterborne polyurethane (WPU) chains, resulting in improved mechanical properties. The elastomer exhibits excellent room temperature phosphorescence (RTP) that remains stable in water, acid, alkali, and organic solvents, even at high temperatures of 160 °C. Notably, the phosphorescence intensity increases threefold under 200% strain, demonstrating reversible mechanical responsiveness. This behavior is attributed to strain-induced microstructural changes that suppress non-radiative transitions and vibrations of NPR. The study highlights the potential of this supramolecular elastomer in applications such as information security and encryption. The material's stability and tunable phosphorescence make it a promising candidate for advanced luminescent materials with mechanical responsiveness.