Abstract: Alkali in concrete reacts with amorphous silica contained in concrete aggregates, then alkali-silica reaction (ASR) gel generates on the aggregates surface. Water absorption by the gel leads to concrete cracking. In order to understand the influence of various factors on the expansion of ASR, a series of experiments were carried out to control the content of rock powder, temperature, humidity, alkalinity and particle size of rock powder. The results showed that the higher the temperature, humidity and alkalinity, the more intense the ASR expansion reaction was, and the expansion trend expanded to different degrees with the increase of age, but the rock powder did not show the alkali active expansion reaction in theory. The increase of the content of 0.08 ~ 0.16 mm quartz sand powder could effectively inhibit the expansion of mortar at the later stage, while the quartz sand powder with particle size less than 0.08 mm had no obvious effect on the expansion of ASR, which can effectively improve the volume stability of the specimen at the later stage to a certain extent.