Germanium glass has attracted much interest because of its potential application as the optical waveguides and communication devices. In this work, germanium glass was prepared, exhibiting the blue luminescence at the 410nm from the Ge2+. The influence of SiO2 addition in the germanate glass on the 410nm luminescence of the Ge2+ was observed. The SiO2 addition promoted the formation of Ge2+, which is because the Si4+ ions can deprive the O2- ions from the Ge4+ ion caused by the lower optical basicity of Si4+ ions than Ge4+ ion. The germanium glasses containing the Ag nano-clusters were prepared using ion-exchange method. The influence of SiO2 concentration on the size of Ag nano-clusters was observed, which stabilize the size distribution and lead to the miniaturization of Ag nano-clusters. The Ag nano-clusters size dependence of their photoluminescence was observed in germanate glasses, and the tunable photoluminescence of Ag nano-clusters was obtained by controlling the size of Ag nano-clusters. It is noticed that the Ag nano-clusters formed in the germanate glass showed the white light emission characteristic excited at the blue chip, exhibiting the practical application as the blue converted white light-emitting diodes.