One-dimensional (1D) photonic crystal structure model was theoretically analyzed through analytical expressions with various structural parameters. The bandgap characteristics of the 1D photonic crystal resulting from the structural parameters were further simulated by a three-dimensional time domain finite difference numerical method. The results show that the bandwidth and center frequency of the 1D photonic crystal bandgap are significantly influenced by hole period and radius, InGaAsP waveguide width, refractive index of bottom cladding, and filling factor. A 1D photonic crystal nanobeam cavity is successfully designed for a Q-factor up to 104 with a designated resonant wavelength of 1 561.7 nm, showing the validation and practicability of the aforementioned results. The study of bandgap characteristics of 1D photonic crystal structure produces an important effect on the integrated photonic components such as formed lasers and modulators.