The spectral Properties of Yb3+ are investigated in fluorophosphate gi￣ withdifferent [PO3]- contentS. In fluorophosphate glasses the results indicate that as the [PO;]content increases in glasses; the stimulated emission cross section of Yb3+ increases; and theabsorption and emission Peaks shift to longer wavelengths;showing the Nephelauxeticeffect.Also; with the increase of [PO3]- content in the glass;more OH- exists in theglass;exertS strong influence on the fluorescence lifetime of Yb3+.