The present invention discloses a separation passageway module comprising a plurality of inclined plates, at least one suction pipe, and a buoyancy regulator. The inclined plate passageways are comprised by a plurality of inclined parallel plates. The inclined plate passageways have an opening at either the lower end or the upper end. In the case of having an opening at the lower end, suspension flows into the passageways from the lower end to carry out settling separation and to thereby generate clear liquid at the upper end of the inclined plate passageways. On the other hand, in the case of having an opening at the upper end, suspension flows into the passageways from the upper end to carry out floating separation and to thereby generate clear liquid at the lower end of the inclined plate passageways. One end of the suction pipe is connected to the upper end or lower end of the inclined plate passageways for drawing the clear liquid. The buoyancy regulator adjusts the buoyant force of the separation passageway module so as to make the buoyant force and the gravity of the separation passageway module reach a specific relationship. Furthermore, the present invention discloses the structures of a suspension separation unit and a suspension separation boat.