The blue and cyan amorphous photonic color glazes were prepared with the addition of 2%-7% niobium pentoxide to Na2O-K2O-MgO-CaO-Al2O3-SiO2 ceramic glaze. The effect of Nb2O5 addition on the glaze color, phase-separated structure and elemental distribution was investigated by UV-Vis reflection spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscope, transmission electron microscope, and the regulation mechanism on the structural color of amorphous photonic was analyzed. The results indicate that the [NbO4] tetrahedra transforms into [NbO6] octahedra as the content of Nb2O5 increases, which exists as network oxides, causing a decreased viscosity of the glaze melt at high temperatures and an increased size of the phase-separated droplets. Also, a large enrichment of Nb2O5 improves the refractive index difference between the two phases, leading to the wavelength of amorphous photonic structural coloration moving to the long-wave direction and a transition of the glaze color from blue to cyan.