Grinding machine with automatic positioning function

The utility model discloses an automatic positioning grinding machine which comprises a machine base, a third roller body is arranged at the top end in the machine base in a rotating mode, second gears are fixed to the two sides of the third roller body, a transmission assembly is assembled between one side of the third roller body and the second gears, and a first roller body is arranged at the end, close to the top end, in the machine base in a rotating mode. An air cylinder is installed at one end of the bearing frame, the end, away from a piston rod, of the air cylinder is fixedly connected with the inner wall of the machine base, a first baffle is fixed to the top end, located between the third roller body and the second roller body, of the machine base, a scraper bucket is fixed to one end of the machine base, and one end of the scraper bucket is tightly attached to the first roller body. When the distance between the first roller body and the third roller body or the distance between the third roller b