The invention relates to a pulping machine. The pulping machine comprises a cylinder. A feeding copper is arranged at the top of the cylinder, and a first smashing device is arranged in the feeding copper; a filtering net and a rotating shaft are arranged inside the cylinder, the lower end of the rotating shaft penetrates through the filtering net and penetrates out of the bottom of the cylinder, first vertical plates are connected to the two sides of the rotating shaft above the filtering net through first connecting rods respectively, first blades are arranged on one sides of the first vertical plates, second blades are arranged on the rotating shaft, and the two sides of the rotating shaft below the filtering net are connected with second vertical plates through second connecting rods respectively; a first annular water spraying pipe is arranged on the inner side of the top of the cylinder, and a second annular water spraying pipe is arranged inside the cylinder below the filtering net; a first discharging opening is formed in the side wall of the cylinder, a three-way pipe joint is connected to the first discharging opening, and one connector of the three-way pipe joint is provided with a returning valve and connected with a returning pipe. By means of the pulping machine, pulp with the improper grain size can be newly fed and smashed, and the smashing effect is good; the inside of the cylinder can be cleaned.