Large-variable-diameter submarine pipeline cleaning device

The invention discloses a large-variable-diameter submarine pipeline cleaning device which comprises at least one pipe clearing unit. Each pipe clearing unit comprises a spindle, two ends of the spindle are both fixedly connected with guiding discs, the outer diameters of the guiding discs are matched with the minimum inner diameter of a pipeline, a seal plate adjacent to the guiding discs are arranged behind the guiding discs and is fixed to the spindle, the outer diameter of the seal plate is matched with the maximum inner diameter of the pipeline, the seal plate is formed by stacking at least two flower-shaped blades, petal structures of every two adjacent flower-shaped blades are arranged in a staggered way, and the minimum outer diameter of the seal plate is matched with the minimum inner diameter of the pipeline after backward folding and deformation. A plurality of elastic arms are arranged behind the seal plate located the front end. The elastic arms are of cantilever structures and are obliquely arra