A further recovery system for residual heat of flue gas, comprising: a housing of upright thin-wall hollow cylinder shape, a rotating core coaxially installed in the upper part of the housing and capable of rotating around its central axis, a partition plate installed in the housing and passing through the central axis of the housing and the rotating core, a baffle plate, a spray device, and a water-water heat exchanger with a heat release unit connected to a water inlet and a water outlet of the spray device; wherein the rotating core is a upright thick-wall hollow cylinder, the longitudinal cross section of the side wall of the rotating core is honeycomb-like, the interiors of which are coated with desiccant material(s), the partition plate divides the internal space of the housing and the rotating core into an air flow channel and a flue gas flow channel, a plurality of baffle plates are respectively installed between the top of the housing and the top of the rotating core, between the top of the rotating core and the top of the partition plate on the flue-gas-flow-channel side, between the bottom of the rotating core and the partition plate on the air-flow-channel side, and between the bottom of the rotating core and the housing on the flue-gas-flow-channel side, the top of the rotating core on the air-flow-channel side forms an air flow channel inlet, an air flow channel outlet is provided in the lower wall of the housing on the air-flow-channel side, a flue gas flow channel inlet and a flue gas flow channel outlet are respectively provided in the lower wall and upper wall of the housing on the flue-gas-flow-channel side, and the spray device is installed in the flue gas flow channel in the lower part of the housing. a housing of upright thin-wall hollow cylinder shape, a rotating core coaxially installed in the upper part of the housing and capable of rotating around its central axis, a partition plate installed in the housing and passing through the central axis of the housing and the rotating core, a baffle plate, a spray device, and a water-water heat exchanger with a heat release unit connected to a water inlet and a water outlet of the spray device; wherein the rotating core is a upright thick-wall hollow cylinder, the longitudinal cross section of the side wall of the rotating core is honeycomb-like, the interiors of which are coated with desiccant material(s), the partition plate divides the internal space of the housing and the rotating core into an air flow channel and a flue gas flow channel, a plurality of baffle plates are respectively installed between the top of the housing and the top of the rotating core, between the top of the rotating core and the top of the partition plate on the flue-gas-flow-channel side, between the bottom of the rotating core and the partition plate on the air-flow-channel side, and between the bottom of the rotating core and the housing on the flue-gas-flow-channel side, the top of the rotating core on the air-flow-channel side forms an air flow channel inlet, an air flow channel outlet is provided in the lower wall of the housing on the air-flow-channel side, a flue gas flow channel inlet and a flue gas flow channel outlet are respectively provided in the lower wall and upper wall of the housing on the flue-gas-flow-channel side, and the spray device is installed in the flue gas flow channel in the lower part of the housing.