The invention relates to an integrated absorption heat-exchanging unit, belonging to the field of the heating and hot water supply devices and comprising a hot-water absorption heat-exchanger and a normal water-water heat exchanger which are combined, wherein, the hot-water absorption heat-exchanger adopts the means of two-level evaporation and two-level absorption. The unit comprises a generator, a condenser, a low-pressure absorber, a high-pressure absorber, a low-pressure evaporator, a high-pressure evaporator, a solution heat exchanger, a throttle device, a solution pump, a water-water heat exchanger and various connecting pipes and accessories. The invention can effectively reduce the backwater temperature of a first-time network of a collective heating system, thus greatly raising the temperature difference of between hot water supply and backwater of the first-time network, further greatly reducing the initial investment to the pipeline system and the power cost of the pump running, creating conditions for utilizing the low-quality heat energy even waste heat, etc., enhancing the comprehensive energy utilization efficiency of the system and reducing the heat supply cost.