Nano-composite Phospho-Silicate (SiO2 - P2O5) co-doped with trivalent (Ho3+) and (Yb3+) ions, respectively are considered as promising materials for photonic application. The nano-composite samples were prepared and their unique optical spectroscopic and structural properties were studied as a function of constant concentration of Ho3+ions at (0.5) mol. % and different concentrations of Yb3+ ions at (0.5, 0.1 and 1.5) mol. % and elevated temperature. The samples structure was studied using X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR). Moreover, the crystallite sizes were increased by increasing the Yb3+ ions concentrations at 900oC to give the following values 11.7, 16.96 and 33.76 nm for (0.5), (0.1) and (1.5) mol.% of Yb3+ ions, respectively. Optical studies were measured by using the spectrophotometer in wavelength range 300–2500nm.The refractive index (n) was calculated for the prepared samples, it was found to be strongly affected by structural rearrangement resulting from the elimination of the solvent and it increases by increasing phosphate concentrations and annealing temperature, It was increased from (1.59 to 1.67) and from (1.75 to 1.78) at constant wavelength 550 nm after annealing at 300 and 9000C for (0.5, 0.1 and 1.5 mol. % of Yb3+ ions), respectively. The photoluminescence (PL) confirms that the phospho –silicate could be a promising candidate to be used for up-down –conversion application.