Abstract: Bacterial cellulose (BC), an extracellular polysaccharide obtained from microbial fermentation, is an eco-friendly bio-based material, with unique properties, including high purity, high water-holding capacity, excellent tensile strength and bio-compatibility. It shows broad application prospects of many fields such as biomedicine, chemical and food industry. In this review, the structure, unique properties, preparation and modification of BC, are respectively presented. In addition, the research progress of BC composites’ applications in environmental field (adsorption, filtration and photocatalysis) is reviewed. Finally, the existing challenges and future prospects are summarized.