The invention discloses a pulp making and pulping washing device for production of repeatedly extruded cardboards. The device comprises a feed hopper, a pulp making bin and a pulp washing bin, the pulp making bin communicates with the paper washing bin through a filtering bin, a first filter screen is arranged in the connecting position of the filtering bin and the pulp making bin, a second filter screen is arranged in the connecting position of the filtering bin and the pulp washing bin, a pulp pump is arranged in the pulp making bin, the feeding position of the pulp pump and the bottom of the pulp making bin communicate with a pulp sucking tube, the feed hopper is arranged at the upper part of the pulp making bin through a first support, and the external of the feed hopper is provided with a first motor through a second support. A plurality of groups of blades are arranged on a same motor shaft, and the blades which compose a slicer are superposed in a staggered manner to process a raw material into enough thin slices, so the processing quality is improved, and the processing efficiency is increased.