The invention relates to a hanging type roller mounting and replacing device. The hanging type roller mounting and replacing device is characterized by comprising a moving trolley, a base, a steel frame, a sealing cover plate supporting plate, a shaft neck supporting device, a shaft head sleeve, a water tank and a quadrate steel frame component, wherein two rollers are mounted at two sides of the base; guide rails are arranged below the rollers; two parallel guide rails extend into a space in the bottom part of the water tank; the steel frame is arranged on the base; the shaft neck supporting device and the shaft head sleeve are arranged on the steel frame.