Abstract: By using the transmission matrix method, the matching matrix and transmission matrix of one-dimensional functional composite structure photonic crystal were given. On this basis, we studied the interface state of one-dimensional functional photonic crystals, and studied the influence of refractive index endpoint value, thickness of medium and incident angle on the position of interface state. The results show that interface state appears at the position where the imaginary part of the total impedance is 0. For functional media, when the initial endpoint value of refractive index increases, the position of interface state shifts red with the band gap, when the endpoint value of refractive index increases, the position of interface state shifts red  with the band gap. When the thickness of the medium increases, the position of the interface state shifts red with the band gap. When the incidence angle increases, the position of interface state shifts blue with the band gap. Therefore, the position of interface states can be adjusted by functional photonic crystals.

Key words: one-dimensional photonic crystal, reverse symmetric structure, impedance, interface state