The Er 3+ –Yb 3+ co-doped silicate glasses have been prepared and the temperature dependence of the fluorescence intensity ratio (FIR) of the green up-conversion emissions about 526nm and 549nm in the range of 296–723K is investigated. The maximum sensitivity and the temperature resolution derived from the FIR technique of the green up-conversion emissions are approximately 0.0033K −1 and 0.2K, respectively. The results imply that Er 3+ –Yb 3+ co-doped silicate glass can play an important role in high temperature measurement.