Abstract: There are lots of lithoid cultural relics with high value of research, art and travel development. However, many relics are in dangerous due to the long-term destroy from the nature or human being, especially acid rain caused by human activities has a serious influence on the relics. In this paper, the fact that acid rain is endangering Leshan Dafou is analyzed firstly, and its mechanism and factors are explored. To protect lithoid cultural relic of red layer, therefore, polluted environment should be improved.