The invention relates to a flue gas pretreatment and carbon dioxide collecting, purifying and recycling device which comprises an absorber, a barren-rich liquor heat exchanger, a heat pump system, a heater, a reproducer, a flash evaporator, a steam compressor and a cyclone separator, wherein an absorption heat pump effectively converts reaction heat of the absorber into heat needed by the reproducer, the temperature of the barren liquor can be reduced when steam recompresses a heat recovery system, and the produced flash evaporated steam is heated up through the steam compressor, and then returns to the bottom of the reproducer; high-temperature steam produced by the heater is led into the bottom of the reproducer from the top of the heater, and the produced high temperature rich liquor can be led into the reproducer from the upper part and the middle part of the reproducer. The device has the advantages that the energy consumption is low, the treatment effect is good, the carbon dioxide collecting purity and efficiency are high, and a unique flue gas pretreatment and carbon dioxide collecting and purifying manner is adopted. The device can obtain CO2 with the purity of 99.9% within the pressure range of 0.1-1MPa, and saves more than 30% energy when compared with a device adopting a traditional technology.