The microstructures of a whangee (a kind of bamboo) were observed with a scanning electron microscope (SEM). It showed that the whangee is a kind of natural cellular biocomposite consisting of countless bamboo cells. The bamboo cells are columnar and all of them are parallel with the surface of the bamboo. The observation also showed that the walls of the bamboo cell are a kind of fiber-reinforced biocomposite with bamboo fiber-spiral mcirstructure. Based on the SEM observation, a kind of biomimetic composite with the fiber-spiral structure was fabricated. The fracture toughness of the composite was investigated and compared with that of the conventional composite with parallel-fiber structure. It showed that the fracture toughness of the biomimetic composite is markedly larger than that of the conventional composite.