Abstract: Yb³⁺ doped fluorophosphate (FP/Yb) glasses with emission cross section and fluorescence lifetime as high as 0.8388×10^-20 cm² and 2.3 ms were developed, and AlF3 content is proved to decrease the lifetime obviously. Large scale glass casting procedure shows high T_x-T_g doesn0t make better casting crystallization stability in certainty. Although Yb laser is difficult to be obtained in FP glass, a 230 mw laser was still achieved from 2 mm thick samples under 976 nm LD excitation because of the large gain parameter( σ_emi*τ_f ) of the FP/Yb glass. Lasing test also proved the relationship between laser output and gain parameter. Combined with its wide and flat effective gain property, this FP/Yb glass is a practical new potential material for low power ultra-short pulse application.