This work highlights some physical properties on langbeinite K2Mg2(SO4)3:Dy3+ sulfates which were prepared by high temperature solid state reaction technique. X-ray powder diffraction confirmed the high purity of the obtained phases. These sulfates crystallize in the cubic phase with space group P213.Several spectroscopic measurements on the synthesized samples were carried out: Fourier transform infrared spectroscopy showed the different vibration modes of sulfate group, the ultraviolet–visible–near infrared absorption spectroscopy revealed Dy3+ transitions from the ground state 6H15/2 to different excited levels and the emission spectra in the visible region revealed four emission bands originated from the 4F9/2 level to the 6H15/2, 6H13/2,6H11/2 and 6H9/2+6F11/2 levels of Dy3+ ions. Moreover, the temperature dependence lifetime of this emitting level can be explained in terms of the thermalization effect.