The invention discloses a self-walking type pipeline inner wall overhaul all-in-one machine which comprises a machine body. A walking mechanism, a functional appliance rack, mechanical arms and a signal generator/receiver are arranged on the machine body; the walking mechanism comprises a main beam and radial fixing devices arranged at the two ends of the main beam; each radial fixing device comprises a main beam sliding block, a sliding disc and sliding shoes; the walking mechanism is fixed to the inner wall of a pipeline through the sliding shoes; the sliding disc of at least one radial fixing device can move forwardly and reversely relative to the main beam; the sliding discs are driven by sliding disc air cylinders arranged on the main beam; the main beam is divided into a front half section and a rear half section which are mutually independent; the front half section of the main beam is connected with the rear half section of the main beam through a rotation component; and various functional appliances are stored on the functional appliance rack. The invention further discloses a walking method of the self-walking type pipeline inner wall overhaul all-in-one machine. The self-walking type pipeline inner wall overhaul all-in-one machine can freely walk on the inner wall of the pipeline, and pipeline flaw detection, cutting and repair can be realized.