The invention discloses high-toughness plastics and a ruler prepared from same, which belongs to the field of preparation of school supplies. The preparation method comprises the following steps: slicing bamboo into bamboo splits, soaking the bamboo splits in biogas solution, activating bamboo fibers by utilizing enzyme produced by microorganisms in the biogas solution, sun-curing and aging the bamboo fibers to further reduce a binding force among the fibers, mixing the NaOH solution and the bamboo splits at a high temperature to promote the slide and swelling of micro filament layers, treating by using liquid nitrogen, forming icy crystals in fiber cells, grinding by using a stone mill, breaking the icy crystals in the cell walls under the pressure effect, separating the fibers to form micro-nano fiber whiskers, mixing the micro-nano fiber whiskers and specially-shaped polyethylene powder polymerized under an electric field condition according to a given ratio, injection molding, grinding, and printing scales, thus obtaining the high-toughness plastic ruler. The ruler obtained in the invention is benefited from the high toughness of the bamboo fibers, and is high in impact resisting strength and unlikely to break, the service life of the high-toughness plastic ruler is greatly prolonged compared with the traditional plastic ruler, and the ruler can be widely popularized and used.