Purifying device and method for dusty gas

The invention relates to a purifying device and a purifying method of dusty gas. The purifying device comprises a heat-tube heat exchanger, a particle settling chamber, a circulating water unit, a polymer packing filter, an atomizing chamber, a diameter-variable separating device and a heat destructing device, wherein the heat-tube heat exchanger is filled with a circulating condensate, and comprises a cooling end and a heating end; the particle settling chamber is arranged on one side of the bottom of the purifying device and in a position lower than an inlet of the purifying device; the circulating water unit comprises a circulating water tank and a circulating water control pipe which are communicated with each other; the circulating water tank is arranged on the other side of the bottom of the purifying device and communicated with the particle settling chamber through a filter hole; the polymer packing filter is arranged at the middle part of the purifying device and in a positionhigher than the inlet of