A humidity sensitive one-dimensional photonic crystal structure is designed by use of two-dimensional nano materials with a periodic arrangement, and then based on the optical properties of the transfer matrix of multilayer media, the humidity sensitive optical properties and humidity sensitive band gap properties of the transmission spectrum of the designed sensing structure are studied, as well as the relationship between environmental humidity and the band structure of one-dimensional photonic crystal under the two light propagation modes of TE and TM. The results show that in TE and TM modes, the one-dimensional photonic crystal has an obvious photonic band gap in the range of 0%～100% relative humidity, and the start wavelength, termination wavelength and band gap width of the photonic band gap change regularly with the environmental humidity.