In this study, experiments with various parameters have been conducted to design the optimun TiO2/UV system for the simultaneous removal of SO2 and NOχ. Removal rate with TiO2 thin film tubular type reactor combined with a 1kW UV-A lamp(365 nm) was higher than that with the annular type and a 20 W UV-C lamp(250 nm) due to higher intensity. In terms of reaction temperature, while NOχ was removed constistently well except for relatively high initial concentration of 150-200 ppm, removal rate of SO2 was decreased as reaction temperature increased. The effect of additive gas on the removal rate indicated that oxygen was better than air becaure N2 in air was involved in the reaction with 0 species to produce NOχ. Increased residence time in the reactor showed the positive effect on the removal rate, and with the same residence time reactor size did not make a difference. All these results were exprssed by the defined factor R which could be effectively applied to the real system.