A corrosion-resistant air preheater capable of slowing down dust deposit, comprising a shell (1), wherein an air inlet (2) is fixedly formed in the side wall of the shell (1), an air outlet (3) is fixedly formed in the side, away from the air inlet (2), of the shell (1), a flue gas through pipe (4) is fixedly arranged on the inner side wall of the shell (1), rotating assemblies are arranged on the outer side wall of the flue gas through pipe (4), a flue gas inlet box (8) is fixedly arranged at the top of the shell (1), a flue gas inlet (5) is fixedly formed in the top of the flue gas inlet box (8), a dust removal device is arranged on the inner side wall of the flue gas inlet (5), a dust discharge mechanism is arranged on the side wall of the flue gas inlet (5), a flue gas outlet box (22) is fixedly arranged at the bottom of the shell (1), and a flue gas outlet (6) is fixedly formed in the bottom of the flue gas outlet box (22).