Upconversion fluorescence emission of Er^(3+)-doped oxyfluorosilicate glass excited at 975 nm is experimentally investigated. The results reveal that the intense green and red emission, and weak blue emission centered at 525, 543, 655, and 410 nm, respectively. A two-photon upconversion process is assigned to the green and red emission while a three-photon process is responsible for blue upconversion. The possible upconversion mechanisms are discussed based on excited state absorption and energy transfer between excited Er^(3+) ions. The intense upconversion fluorescence of Er^(3+)-doped lead oxyfluorosilicate glass may be a potentially useful material for developing upconversion optical devices.