The aim of this study is to investigate the behaviour of the calcium silicate brick masonry wall exposed to sulphate condition. This paper presents some result about the effect of sodium sulphate attack on the elasticity of the calcium silicate brick masonry structures. All specimens were cured under polythene sheet for 14 days in environmental controlled room with temperature of 25± 2°C and 80 ± 5% relative humidity. After curing, the specimens were exposed to sodium sulphate solution before tested at 14, 28, 56 and 180 days respectively. As a result, the modulus of elasticity of the calcium silicate brick masonry wall reduces with the increase of sulphate concentration.