Recycling system for heat and moisture in flue gas of coal-fired power plant and recycling method of recycling system

The invention discloses a recycling system for heat and moisture in flue gas in a coal-fired power plant and a recycling method of the recycling system. The recycling system comprises a boiler (1), an air preheater (2), an electric dust collector (3), a desulphurization tower (4) and a chimney (5) which are sequentially connected, a primary heat exchanger (6) is arranged between the electric dust collector (3) and the desulphurization tower (4) and connected with the boiler (1) by a pipeline, and a secondary heat exchanger is disposed between the desulphurization tower (4) and the chimney (5). The moisture in the flue gas can be recycled, the waste heat in the flue gas can be sufficiently utilized, water consumption of the power plant can be effectively reduced, and energy utilization rate is effectively improved. In addition, partial sulfur dioxide and mercury elements in the flue gas can be removed, and pollution of the flue gas of the power plant to air is reduced.