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 mortars 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 mortars and compressive strength is greatly higher control mortars 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.