Rare earth doped chalcogenide glasses is an important way to achieve mid- infrared luminescence. By designing photonic crystal structure on the sample, the luminous efficiency of the glass can be enhanced greatly. Tm3 + doped chalcogenide glass is prepared and the related optical properties are tested. Photonic crystal structure on the glass sample is designed to enhance the emission of 3.73 mm fluorescence which generated by the transition of Tm3 + ions. Finite difference time domain (FDTD) simulation shows that the photon density of states at 3.73 mm is greatly enhanced in the sample with designed photonic crystal, the Purcell amplification factor can be over 50 times than that in the bulk sample. This greatly increment of the photon density of states and the Purcell factor provides a theoretical basis for the enhancement of luminescence. The results of this work can be used to achieve high efficiency infrared light source device.