Through the Illumina MiSeq analysis within V3-V4region of 16S rRNA gene, the response of microorganisms to scCO₂ and its feedback on the mineral interaction in scCO₂-saline-sandstone system was investigated. The results showed that biomass was affected by pH value. The initial pH was 7.02 and biomass was 11.02×10⁶ gene/mL. And the pH dropped to 5.65 and biomass decreased to 0.26×10⁶ gene/mL at 30^th-day. However with the dissolution of minerals, the pH increased to 5.87 and biomass increased to 4.61×10⁶ gene/mL at 90^th-day. In the community structure, phylum Proteobacteria (52.60% (30d), 55.34% (90d)) and phylum Firmicutes (46.89% (30d), 43.89% (90d)) were dominant phylum. At the genus level, Exiguobacterium, Citrobacter, Acinetobacter and Pseudomonas were dominant genus at 30^th and 90^th-day. Acid-producing bacteria (Exiguobacterium, Acinetobactera and Pseudomonas) promoted the dissolution of feldspar and clay, and the concentrations of K⁺, Na⁺, Ca²⁺, Mg²⁺ and T-Fe were higher than those in blank group. Iron-reducing bacteria (Citrobacter) increased the ratio of Fe(Ⅱ)/Fe(Ⅲ). Biofilm showed an adsorption function of Ca²⁺, Mg²⁺ and Fe²⁺. At last, the SEM results showed that the micron-mediated precipitation of siderite appeared before the blank group. Therefore, the adaptable bacteria in the scCO₂-salt-sandstone system could promote the mineral dissolution and carbonates capture.