Using process software Aspen Plus of coal-fired power plant carbon dioxide capture flue gas pretreatment system simulation, studied the flue gas quantity、packing layer height、absorbent in quantity and absorbent in temperature, influence on the content of SO2 and cooling in the flue gas outlet. The results showed that the content of SO2 and temperature in the flue gas outlet, increase with increasing the flue gas quantity, decrease with increasing the packing layer height and absorbent quantity, increase with the rising of absorbent temperature.