Mortar was made with 1.185.00mm，600μm1.18mm，300600μm and ＜300μm waste glass replacement of natural sand at levels（by mass） of 30%, 60% and 100%. Mortar specimens were tested for their compressive strength and splitting tension strength at 20，300，400，600，800 and 900℃. The experimental results show that the mortar which was made with ≥300μm waste glass replacement of natural sand, its strengths at room temperature are lower than control mortars and decrease with increase of temperature. The mortar which was made with＜300μm waste glass replacement of natural sand, its splitting tension strength is slightly higher than control mortars and compressive strength is greatly higher control mortars at room temperature. It was found that mortar strength of all mixes reduces with elevation of temperature, a good linear relationship between strength and heating temperature is present, most of the correlation coefficients are greater than 0.980.The waste glass for particle size ＜300μm and replacement rate of more than 60% can get more than 1.25 high temperature enhancement coefficient and can significantly improve high temperature performance of mortar.