Visible lasers and amplifiers have potential applications in the fields of optical data storage, spectroscopy, biomedical and optical local area networks. In this study, Tb 3+ -Yb 3+ co-doped fluorophosphate glasses were synthesized and properties of the visible emission at 0.54 µm were investigated. A upconversion excitation efficiency from Yb 3+ to Tb 3+ was studied by evaluations of a cooperative energy transfer efficiency from Yb 3+ to Tb 3+ (η CET ) and a back-transfer efficiency from Tb 3+ to Yb 3+ (η BT ) which give positive and negative contribution to upconversion excitation, respectively. The η CET was as high as 25 %, and the η BT was less than 1 % in the fluorophosphate glass. This indicates that Tb 3+ -Yb 3+ co-doped fluorophosphate glass is promising as new laser and gain media in the 0.54 µm band.