The photonic band gap (PBG) and transmission of one-dimensional photonic crystal are studied with two simulation software: MPB and MEEP in microwave region. The influence of the different ratio and the relative dielectric constant of the medium on PBG is studied. The simulation result shows that as the ratio of the high relative dielectric medium increases or the high relative dielectric constant itself increases, the center frequency of the PBG will decrease slowly and the width of the PBG will firstly increase and then decrease, which forms a maxima. A kind of material of photonic crystal is fabricated with dielectric sheets which consists of a BaTiO3 powder and PDMS and foam sheets arraying in cyclical order. A one-dimensional photonic crystal is made, of which the high relative dielectric constant is 4.5, the low relative dielectric constant is 1, the ratio of materials is 1∶1, the lattice constant is 10 mm and the cycle is 5. The transmission of that one-dimensional photonic crystal is measured experimentally. Result shows that is the region from 8~12 GHz, the center frequency of the PBG is 9.3 GHz and the width of the PBG is 500 MHz.