Based on the desulphurization and denitration for sintering flue gas of 7×105 m3/h sinter machine, the oxidation of ozone to flue gas and absorption of oxidation products (NOx, SO2) by the semidry process in the practical engineering applications were studied. The results indicated that the location of ozone injection had little effect on the oxidation of nitrogen oxides in duct and the injection grille guaranteed the uniform mixing of ozone and flu gas. The temperature of flu gas at the exit of the absorption tower had a great effect on the denitration, and the absorption efficiency of NOx decreased with the increasing of temperature. When the temperature was higher than 95 ℃, the denitration efficiency was zero. However, the change of temperature at the exit of the desulphurization tower had nearly no effect on SO2 absorption. The continuous operation data obtained of the optimized desulphurization and denitration system for sintering flue gas indicated that the average values of the outlet SO2 and NOx were 16.83 and 72.33 mg/m3, respectively, which both achieved the requirement of system design. The system operating cost was 1011 yuan/t. Compared with the activated carbon flue gas purification technology and circulating fluidized bed＋SCR technology, the ozone oxidationsemidry absorption synergistic desulfurization and denitration process had obvious advantages.