In this work, Pr3+ ion-doped Ge20Ga15-xSbxSe65 (x = 0, 5, 10, in mol%), Ge20Sb15-yInySe65 (y = 5, 10, in mol%), Ge20Ga15-zInzSe65 (z = 0, 5, 10, in mol%), and Ge20Ga5Sb10Se60I5 glasses were prepared. The structural units, thermal properties, and optical properties of these glasses were analyzed. In addition, a comprehensive comparison study of the effects of metal ions (Sb, Ga, and In), S/Se ratio, and I content on the mid-infrared (MIR) luminescence of Pr3+ ions was conducted. Under a 1.55-mu m laser pump, 0.2 mol% of Pr3+ ion-doped chalcogenide glasses performed strong photoluminescence in the wavelength range of 3.5-5.5 mu m. Results indicated that the Sb-containing glass performed the strongest emission intensity among the studied glasses. Moreover, halogen element I can reduce the phonon energy of the matrix, which is beneficial to the luminescence of Pr3+ ions and provide significant possibilities for developing MIR lasers and amplifiers.