Photonic crystals are periodic structures made by two or more different refractive indices materials. The important feature of photonic crystals is photonic band gap. In this thesis, the main object we study is about plasma photonic crystals. We use the transfer matrix method to calculate the transmission spectrum. In the first topic, we focus on a one-dimensional photonic crystals. This photonic crystals are composed by SiO2 and air, and with one defect layer made by magnetized plasma. We change the plasma density and magnetic field and then use the transfer matrix method to calculate the transmission spectrum. In the second topic, we use a one-dimensional photonic crystals which composed by SiO2 and plasma layer. We change the incidence angle and magnetic field and then use the transfer matrix method to calculate the transmission spectrum. In the last topic, we study the effect of magnetic field on the photonic band gap of plasma photonic crystals. This plasma photonic crystals are composed by SiO2 and plasma layer, just the same with the second topic. We change the incidence angle and magnetic field and then calculate the photonic band gap of this plasma photonic crystals.