Monodisperse polystyrene(PS)@SiO2 core-shell nanometer microspheres are prepared by emulsion polymerization combined with an improved Sto ?ber method, PS@SiO2 particles are then dispersed in the precursor of poly(ethylene glycol) phenyl ether acrylate (PEGPEA), forming a fast photopolymerization capture regular array after forming a non-dense particle array, and preparing a mechanically discolored photonic crystal film. The structure, optical properties and photochromic properties of photonic crystal thin films were characterized and tested by SEM and optical fiber spectrometer. The influence of the volume fraction and particle size of PS@SiO2 particles on the structure color of photonic crystal thin films was investigated, and the mechanism of photochromic effect of PS@SiO2 particles on the structure color of photonic crystal thin films was predicted. The results show that the heat treatment by ultraviolet light changes the microstructure order of PS@SiO2 particles and causes them to form the structure of opal photonic crystal. The structure color of photonic crystals gradually changes from red to blue with the increase of PS@SiO2 particle volume fraction or the decrease of particle diameter. Photonic crystal thin film has structural color reflectivity> 60%, tensile strain 70%, sensitivity 2.16 nm/%, response speed 1.9 nm/ms, reflection wavelength tuning range(Δλ)=152 nm. After 100 stretch/release cycles and 3 d recovery at 25 ℃, the structure color of the photonic crystal film remained unchanged. The unique core-shell structure of PS@SiO2 nano-microspheres has elasticity and stretchability. PS improves the refractive index difference between the nano-microspheres and the elastomer matrix, can improve the reflectivity, and can make the structure color of the photonic crystal thin film brighter. During the stretching process, the colloidal particles can remain constant by following the position of the elongated lattice. The negligible rearrangement of the particles makes the color shift of the photonic crystal film completely reversible under strain, so the deformation is elastic and there is no residual strain.