The invention relates to a phototransformation antibacterial particle-modified functional bacterial cellulose compound sol and a preparation method of the composite material. The method comprises the steps of: S1, distribution and activation of inorganic particles; S2, pre-treatment of the bacterial cellulose; S3, preparation of bacterial cellulose nanocrystals; S4, chemical modification of the bacterial cellulose; S5, preparation of the phototransformation antibacterial particle-modified functional bacterial cellulose compound sol; and further preparing different antibacterial composite materials by using the compound sol. The prepared phototransformation antibacterial particle-modified functional bacterial cellulose compound sol has very good stability, and activated inorganic antibacterial particles can form a stable chemical bond effect with modified bacterial cellulose under a certain condition, so that the antibacterial particles are free of agglomeration and are uniformly and stably distributed in the whole system with bacterial cellulose as a matrix material of a product, thereby providing excellent operability for a subsequent application.