Abstract: 【Objective】To reveal the mechanism of microbial weathering of rocks, promote the rock slope to covered with plants, and improve the ecosystem, the effect of Aspergillus niger and its metabolites on the weathering of granite were studied in this research.【Method】An A. niger strain, which is highly efficient in weathering rocks, was isolated and purified from the granite soil. Liquid dynamic culture and electron microscopic analysis were used to study the metabolites produced by A. niger during the fermentation. Effects of the metabolites on leaching of silicon, iron, aluminum, and other elements from granite were studied.【Result】The results indicated that A. niger in the medium containing granite powder can synthesize six kinds of organic acids, including oxalic acid, tartaric acid, succinic acid, malic acid, acetic acid, and citric acid in its fermentation liquors. The contents of these organic acids gradually increased at early stage of fermentation, and then decreased with the fermentation process. Which indicated that A. niger could uptake and utilization those organic acids during growth and reproduction. A. niger synthesizes different amino acids in different fermentation stages, and the medium containing granite powder is beneficial in synthesizing polysaccharides. The results of metabolites of A. niger in liquid dynamic culture indicate that organic acid, amino acid, and polysaccharides can destroy the structure of rocks and release silicon, iron, aluminum, sodium, and other elements from granite. During rock weathering, the metabolites have certain synergistic effect. The effect of the mixture of organic acids, amino acids, and polysaccharides on elements extractions is significantly better than their respective effects.【Conclusion】A. niger and its metabolites, including organic acids, amino acids, and polysaccharides, and their mixture facilitate the weathering of granite, and the effect of weathering granite by A.niger is superior to that of single and mixed metabolites.