Energy transfers and upconversion fluorescence spectroscopy in both Er3+ singly doped and Tm3+-Yb3+ co-doped AlF3-based flouride glass,excited at 970nm,are investigated experimentally.In Er3+:AYF glass,the optium Er3+content for 550nm emission is about at 6mol%,which is 12mol% in AZF glass.With the increase of Er3+ content,the intensity ratio of the red emission to the green emission (Ired/Igreen) is increased in AYF and AZF glass,and the red emission intensity in these gass depends on (Pex)1.6.They are mainly due to a cross-relaxation process between two erbium ions,one in the 4S3/2 and the other in the 4I9/2.In Tm3+-Yb3+ co-doped AlF3-based flouride glass,the concentration quenching of Tm3+ in blue at 476nm is stronger than that in infrared light at 793nm,and the optimum content of Tm3+ for 476nm emission is about 0.1mol%,while it is (0.3—5)mol% for 793nm emission.The concentration quenching of Yb3+ to upconvertion fluorescence is also observed.It may be due to the back-energy transfer from the 3F4 level of Tm3+ to the 2F5/2 level of Yb3+.