Abstract: Due to small diameter of desulfurization tower and high flow rate of flue gas,the flue gas desulfurization and de-dusting are difficult to achieve ultra-low emission.Taking a 300 MW thermal power generating unit as example,the swirling atomization desulphurization and de-dusting integrated technology was upgraded to study the effects of liquid-gas ratio and inlet flue gas temperature on desulfurization efficiency and dust removal efficiency. The results show that the dust concentration of inlet and outlet in desulfurization tower are30 mg/Nm~3 and less than 5 mg/Nm~3,respectively with the swirling atomization desulphurization and de-dusting integrated technology,and desulfurization and de-dusting can complete in the single desulfurization tower without humidification.At a certain liquid-gas ratio,the flue gas inlet temperature and SO_2 concentration have little effect on the efficiency of desulfurization tower,the desulfurization efficiency can be stabilized above 99.29%,and the desulfurization tower dust removal efficiency is as high as 90.84%,indicating the swirling atomization desulphurization and de-dusting integrated technology has good adaptability and system stability.