In the paper the theory of cutting wood fiber on micron-level has been put forward, that is the cutting power of micron flake wood fiber is much smaller than the mechanical power consumed by grinding. Therefore, the manufacture method for micron flake wood fiber is a kind of way of materials preparation, which can economize energy, decrease in consumption and pollution. From the theoretical analysis, only a reasonable cutting-arrangement on direction can significantly reduce the power. So in the condition of reducing power, relying on pure shear to fracture fibers in tissue is the best effort, at the same time through the vertical ultra-high-speed cutting in grain, the micron filament fibers will be cut out. The influences produced by various factors for the formation of flake fibers have been verified through testing, including the improved tool material, the wood grain, the cutting speed and the improvements for locating specimen.Through the improved method for sluggish wood-fiber cutting, not only does this method reduce power consumption, but also decrease the probability of fiber cut off and substantial increase fiber’s length and quality. Moreover, after these flake fibers having been rescheduled, the elastic modulus of fiber MHFB hot pressed out can reach 5171Mpa, and the grip force of that can reach 1933N.