In this paper, a transparent photonic crystal film was designed with tunable mechanochromic properties. The monodispersed SiO2 colloids were self-assembled to form 3D opal photonic crystals and then embedded in elastomeric PDMS to generate the photonic crystal film. The structure and optical properties of photonic crystal films were characterized by SEM, fiber optical spectrometer and digital camera, and their applications in anti-counterfeiting was studied. The results showed that the transparent photonic crystal film exhibited an obvious structural color upon stretching, and the color experienced a continuous blue shift with the increase of tensile strain. Moreover, the photonic crystal film can back to its original state reversibly upon releasing. Even after 100 cycles of stretching and releasing, the photonic crystal film still maintained stable optical properties. Through the patterned design of the photonic crystal film, the hidden pattern of photonic crystal film could be revealed and disappeared quickly by applying or withdrawing the tension, which has broad application prospects in the field of anti-counterfeiting.