The invention relates to a two-stage constant-temperature ammonia-water re-absorption heat pump circulation and heat supply method. A two-stage constant-temperature ammonia-water re-absorption heat pump circulation device comprises a solution loop, refrigerant steam pipelines, a water supply and return pipeline and driving heat sources. The solution loop comprises a high-pressure generator, a high-pressure absorber, a medium-pressure generator, a medium-pressure absorber, a low-pressure generator, a low-pressure absorber, three throttle valves, a solution mixing tank, a solution mixing/separation tank, a solution separation tank, a solution circulating pump, two high-temperature solution heat exchangers, two low-temperature solution heat exchangers and four three-way valves. The refrigerant steam pipelines include the high-pressure refrigerant steam pipeline, the medium-pressure refrigerant steam pipeline and a low-pressure refrigerant steam pipeline. The water supply and return pipeline comprises a water supply pipeline and a water return pipeline. The driving heat sources include the high-temperature driving heat source and the low-temperature driving source. The heat supply method based on the device comprises a water supply and return circulating process, an ammonia solution circulating process, and an ammonia steam pipeline operating process.