The invention discloses a multistage separation oil-water separator, and relates to the technical field of oil-water separation, the multistage separation oil-water separator comprises a separator shell, a
solid-liquid separation chamber, a corrugated coalescence chamber and a
fiber polymerization chamber are sequentially arranged in the separator shell from top to bottom, a primary filtering mechanism is arranged in the
solid-liquid separation chamber, and the primary filtering mechanism comprises a filtering cylinder, a centrifugal cylinder and a mounting plate; the mounting plate is fixed on the inner top wall of the separator shell, the filter
cartridge is obliquely arranged, one end of the filter
cartridge is rotatably mounted on the mounting plate, a water inlet pipeline is arranged on the separator shell, a water inlet port of the water inlet pipeline extends into the filter
cartridge, the centrifugal
barrel and the filter cartridge are coaxially arranged, one end of the centrifugal
barrel is rotatably mounted on the mounting plate, and the other end of the centrifugal
barrel is rotatably mounted on the mounting plate. The high end of the centrifugal cylinder penetrates into the bottom end of the filter cylinder, a
solid waste box is arranged on the side wall of the separator shell, the end, away from the filter cylinder, of the centrifugal cylinder movably penetrates into the solid waste box, step-by-step separation is conducted in different
modes according to oil-water separation characteristics, and the oil-water separation effect is remarkably improved.