A felt product modifying and drying apparatus, comprising: an unrolling device, configured to support a felt product roll and unroll the felt product roll; a modifying tunnel machine, configured to modify a felt product unrolled by the unrolling device; a water washing spraying device, configured to wash the felt product modified by the modifying tunnel machine with water; a drying tunnel machine, configured to dry the felt product washed by the water washing spraying device with water; a rolling device, configured to roll the felt product dried by the drying tunnel machine; and a transmission device, penetrating through the modifying tunnel machine, the water washing spraying device and the drying tunnel machine and configured to transmit the felt product unrolled by the unrolling device to sequentially pass through the modifying tunnel machine, the water washing spraying device and the drying tunnel machine, wherein the modifying tunnel machine comprises: a modifying box, wherein a modifying solution is contained in the modifying box, and at least one section of the felt product on the transmission device located in the modifying box is immersed in the modifying solution; at least one ultrasonic device, configured to accelerate a displacement speed of the modifying solution and an acid solution in the felt product and disposed in the modifying box; a modifying solution circulation and heating system, connected with the modifying box and configured to extract the modifying solution from the modifying box, heat the extracted modifying solution and return the heated modifying solution to the modifying box; and a modifying solution supplementing and acid solution collecting system, connected with the modifying box and configured to supplement the modifying solution into the modifying box and collect the acid solution obtained through displacement. an unrolling device, configured to support a felt product roll and unroll the felt product roll; a modifying tunnel machine, configured to modify a felt product unrolled by the unrolling device; a water washing spraying device, configured to wash the felt product modified by the modifying tunnel machine with water; a drying tunnel machine, configured to dry the felt product washed by the water washing spraying device with water; a rolling device, configured to roll the felt product dried by the drying tunnel machine; and a transmission device, penetrating through the modifying tunnel machine, the water washing spraying device and the drying tunnel machine and configured to transmit the felt product unrolled by the unrolling device to sequentially pass through the modifying tunnel machine, the water washing spraying device and the drying tunnel machine, a modifying box, wherein a modifying solution is contained in the modifying box, and at least one section of the felt product on the transmission device located in the modifying box is immersed in the modifying solution; at least one ultrasonic device, configured to accelerate a displacement speed of the modifying solution and an acid solution in the felt product and disposed in the modifying box; a modifying solution circulation and heating system, connected with the modifying box and configured to extract the modifying solution from the modifying box, heat the extracted modifying solution and return the heated modifying solution to the modifying box; and a modifying solution supplementing and acid solution collecting system, connected with the modifying box and configured to supplement the modifying solution into the modifying box and collect the acid solution obtained through displacement.