In this study the elevated temperatures properties of CO₂sands bonded with high mole ratio sodium silcates were investigated and following results obtained. 1) The CO₂sand has peaks of the compression strength at the temperatures of 200℃ and 500℃ and its strength decreases to 2㎏/㎠ at 690℃. The higher mole ratio binder shows strength at the region of overall temperatures and the sodium silicate with 3.3 mole ratio appears very low strength of under 2.5㎏/㎠ at the peak point. 2) The dehydration reaction of sodium silicate continues up to 500℃ and at the temperatures higher than that, the dehydration does not take place. Near the temperature of 600℃, the silica sand diminishes in its grain sizes with the phase transformation occurred. 3) among organic additives, polyol increases Strength at the temperatures up to 400℃ and has the contrary influence at the temperature higher than hat. The bonding strength of sodium silicate at the temperature region of up to 400℃ is affected by the retained moisture and by the sponge structure changes of formed silica gel. And the addition of polyol has an affect of maintaining higher retained moisture within silica gel. 4) The bonding strength of high mole ratio sodium silicate increases with its content, and for the binder with 3.3 mole ratio, it is necessary to add 6% of sodium silicate for the enough strength. 5) The high temperature compression deformation of CO₂sand decreases gradually at the temperatures below 400℃ and has a linear increase at the temperatures up to 700℃. But the sand has a tendency of sligt increase in deformation at the temperatures above 700℃. With silicate bond softening by fusion, the silicate forms a viscous glass and the rise in compressiveness occurs. 6) The higher mole ratio silicate has a lower deformation. Organic addition produces a lower deformation, though depending upon its material. 7) The expansion of CO₂ sand forms a peak near the temperature of 600℃ with the phase transformation of silica and has the maximum value near 1,100℃. But the sand boned with 3.3 mole ratio sodium silicate decreases gradually its value and comes to a null value at 600℃. 8) when the mole ratio of the binder increases, the expansion of CO₂sand decreases on the contrary. And polyol additive has a considerable effect of absorbing the sand expansion. In conclusion, the addition of polyol to the CO₂sand bonded with high mole ratio sodium silicate causes a good effect of improving the mold strength, which is requested at the region of low temperature of up to 500℃ and of decreasing deformation and expansion.