The invention relates to a macro fiber based on bacterial cellulose nanofiber directional arrangement and a preparing method thereof. Bacterial cellulose nanofibers evenly dispersed after enzyme hydrolysis are directionally arranged under the effect of shearing force and assembled into the nanofiber-based macro fiber. A continuous-preparing system method of the one-dimensional soft material based on bacterial cellulose nanofiber directional arrangement is built by adjusting and controlling the structure, the size and the dispersing degree of the nanofibers, the order degree of the nanofibers and the acting force between the nanofibers. According to the method, solidification forming and crosslinking are integrated, the technological process is shortened, the order arrangement degree of the nanofibers is improved in a drawn mode through the low-crosslinking macro fiber, the high-mechanical-performance macro fiber is prepared, and therefore the excellent mechanical performance and the excellent flexibility of the bacterial cellulose nanofibers are more effectively expanded to the macro size from the nanoscale.