Severe water pollution has placed a heavy burden on the ecological environment on which humans rely. Effective approaches to mitigating this worldwide issue are in great demand. Here in this work, an organic-inorganic bacterial cellulose aerogel was fabricated through a freeze-drying technique and a step-by-step coating method. The as-prepared aerogel possessed an intact three-dimensional porous structure, an ultralow density, and shape recovery performance. Ag2O nanoparticles were uniformly and firmly dispersed on the cellulose skeleton, endowing the as-prepared aerogel with an excellent photocatalytic degradation property of methylene blue and great recyclability. The aerogel with zwitterionic compounds attached through the effect of silane exhibited superhydrophilicity, superoleophilicity, and underwater superoleophobicity as well as underoil superhydrophobicity, and it could separate oil/water mixtures with high efficiency. This environmentally friendly bacterial cellulose aerogel equipped with multifunctionality showed great potential for wide application in water treatment fields.