The invention provides a device for conducting wet process desulfurization and denitrification by means of chimney heat reabsorption. The device comprises a water supply pump, a water inlet pipe, a spiral water flow pipeline, a water outlet pipe, a pipeline protection sleeve, a dilution water storage tank, a water pump, an analog valve, a urea solution preparation tank, a transfer pump, a urea solution storage tank, a urea pump, an external circulation pipeline and the like. By the adoption of the device, exhaust gas energy of a heating pot can be reused, a water circulation heat energy collecting pipeline is designed to serve as an energy collecting mechanism, water in the water circulation pipeline is heated and then is supplied to a water heating treatment link required in the denitrification process through the water outlet pipe, and thus the energy utilization rate is greatly increased. The device for conducting wet process desulfurization and denitrification by means of chimney heat reabsorption is simple in structure, the heat energy utilization rate is increased, and energy losses and the influence on the environment can be effectively reduced.