This paper is about the suppressing of the alkali-silica reactivity of limestone aggregate by using finely ground limestone aggregate. The accelerated mortar-bar expansion test (ASTM 1260) was used to evaluate the effectiveness of limestone powder in suppressing ASR expansion. Three mixes were used, respectively, 15%, 30% and 50% limestone power replacement of the cement. The results showed that deleterious expansions due to ASR could be suppressed by using reactive limestone powder. The effects depended on what the replacement amounts and the ages were. With appropriate replacement amounts, the deleterious expansions due to ASR could be reduced by using reactive limestone powder. Author believes that any type of mineral SiO2 with being grounded to certain fineness can suppress the ASR reactivity of aggregates, and the effectiveness of reactive aggregate powder is better than that of non-reactive aggregate powder. The replacement level that can control expansion varies with the type of mineral SiO2 and fineness of the aggregate powder.