The influential law and mechanism about rock lithology， particle size， stone powder content and specific surface area， clay mineral type and content of artificial sand on the methylene blue value（MB value） were studied. The results show that rock lithology and particle size of artificial sand have less influence on MB value， stone powder content and specific surface area of artificial sand have some influence on MB value； clay mineral type and content affect significantly the artificial sand MB value. Adsorption performance of expansile clay（such as montmorillonite） is much stronger than that of non-expansile clay（such as illite）， the MB value of montmorillonite artificial sand is about 10 times that of illite artifical sand with the same content. For artificial sand with excessive MB value， the key to reducing its MB value is to control the addition of expansile clay minerals and control the content of other kinds of clay minerals.