Fiber bundle filter, using the water level in the filter or filter top-down gravity makes the filter layer compression, Fiber bundle filter material in the solid state, improve the efficiency of the filter layer intercept the impurities, ensure the water quality after filtration. Flush, shangdi shock disturbed by the gas water, make the bunchy Filter material in a suspended state, Filter layer in the adsorption intercept things get clear. So as to realize the bunchy fiber Filter material state loading filtering and orderly loading backwashing the best state. When used by the upper water, bottom water. At this point, under the action of water flow, and under the action of gravity, fiber density adjusting device to promote fiber filter bed run down, fiber filter layer is compressed, its bulk density along the flow direction gradually increased, the filter layer along the water flow direction of porosity by large became smaller, the corresponding filter pore diameter and porosity decreases gradually, thus forming a special ideal state of getting deep pore filter. The filtering process has both lateral deep filter, and the longitudinal deep filter, and the filtering precision is improved effectively. When Filter contaminated need clean renewable, clean water along the reverse direction through the fiber Filter bed, under the action of backwashing water and clean air, fiber density adjustment device to drive the fiber Filter bed upward movement, make the fiber Filter material stretch upwards, achieve loose state, through the mixed gas water cleaning technology, in the process of accumulation and dispersion of the Taylor bubble and hydraulic flushing, fiber Filter material vertically in a state of constantly shake, thus makes the fiber Filter material clean thoroughly, so as to achieve the ideal cleaning effect.