The invention provides a bypass device (13 or 26) for dredging active carbon. The bypass device (13 or 26) comprises a bypass pipeline (131 or 261) communicated with an active carbon source and buffers arranged on the bypass pipeline (131 or 261) at intervals; the distance between two adjacent buffers (132 or 262) is not longer than the fall damage safety distance (H) of the active carbon; each buffer (132 or 262) comprises a buffer chamber (5 or 02) and a gradual declining chute formed in the buffer chamber (5 or 02) and extending from the top to the bottom of the buffer chamber (5 or 02); or a plurality of staggered and inclined slide carriages (03) are arranged in the direction from the top to the bottom of the buffer chamber; and each slide carriage (03) extends from the fixed end of the slide carriage to the bottom of the buffer chamber (02). The fall damage of the active carbon is reduced. The invention also provides a buffer and an absorption tower or an adsorption tower provided with the bypass device.