.Some thermomechanical properties such as expansion, transition temperature and high-temperature viscosity of phosphate glasses with different P2O5 and BaO compositions have been measured. Absorption and fluorescence spectra of the phosphate glasses with different Er3+ doping have also been measured. The Er3+ doping concentration with respect to the maximal fluorescence intensity is 0.75 mol%. The attenuation of the fibre at a wavelength of 1.53 mu m is 12.8 db m(-1). Upconversion of 1.064 mu m Nd:YAG laser pulses into intense green 547 and 667 nm light in the 0.75 mol% Er3+-doped phosphate glass fibre has been achieved. The output power of the two fluorescence signals of green 547 nm and red 667 nm are 178 and 42 mu W, respectively, with an upconversion efficiency of 1.78x10(-2)% and 4.2x10(-3)% respectively.