Strong upconversion luminescence of Er3+/yb3+-doped lead halide tellurite glass under 976nm excitation is demonstrated. Three emission bands centred at 525nm, 545nm, and 655nm resulting from the transitions from the excited states 2H11/2, 4Ss/2, and 4F9/2 to the ground state 4I15/2, respectively, are observed even at 60mW pumping power. The power dependent intensity and the upconversion mechanisms responsible for the luminescence are evaluated and discussed. The obtained results might provide useful information for the developments of upconversion lasers.