The upconversion luminescence spectra of Tm3+/Yb3+-codoped oxyhalide tellurite glasses have been investigated, and the action mechanisms of Tm2O3 content on upconversion luminescence of Tm3+/Yb3+-codoped oxyhalide tellurite glasses were analyzed. The results showed that there exists concentration quenching of Tm3+ in oxyhalide tellurite glasses. With increasing Tm2O3 content, upconversion blue and red emission intensities of Tm3+ first increase, reach its maximum at Tm2O3%=0.1mol%, and then decrease. The obtained results are conducive to increase upconversion luminescence efficiency of Tm3+.