One dimensional photonic crystal was proposed to modify the emission spectrum of BaF 2 scintillation crystal. The photonic crystal was composed of the basic unit, Al 2O 3/MgF 2/Al/ MgF 2. The transmittance spectrum of the photonic crystal and the relevant emission spectrum of the BaF 2 were discussed with relation to period number, metallic layer thickness and its position in the low refractive index material, emission angle etc. Results show that the attenuation of the fast component is less than 5 times and the relative restraint ratio of the slow component is larger than 20 with the designed photonic crystal. The relative restraint ratio of the slow component can be larger than 100 by selecting appropriate detect angle range.