The fluoroaluminate glasses doped with Tm 3+ were prepared. The spectroscopic parameters have been calculated for Tm 3+ doped fluoroaluminate (AYF) glass based on the measured absorption spectra using Judd-Ofelt theory. IR emission and frequency upconversion of Tm 3+ doped fluoroaluminate glass were investigated. The results show that the concentration quenching is more significant for 1.45 μm-emission ( 3F 4→ 3H 4) than for 1.77 μm-emission ( 3H 4→ 3H 6) under the 800 nm excitation. The mechanism of upconversion, excited at 655 nm, was proved to be a simple excited state absorption (ESA) process.