Nanosized yttrium disilicate powders activated with trivalent erbium ions were produced by Sol-Gel known as wet chemical process. The structure and morphology of the synthesized powders were characterized by using X-ray diffraction spectroscopy (XRD), Transmission electron microscopy (TEM) and Photoluminescence spectroscopy. The XRD analysis revealed that the formation of triclinic  a-Y2Si2O7 and monoclinic  b-Y2Si2O7 polymorphs were obtained at 1050  and 1450 , respectively. The photoluminescence properties were also investigated in terms of sintering temperature and doping effect on different polymorphs.