With refractory ethanethiol being the target pollutant, the photocatalytic oxidation of the supported nano titanium dioxide is introduced as the treatment technology. Aanatase-type titanium dioxide catalyst with high activity was obtained by calcination at 450℃. The degradation efficiency was investigated under different gas flow rate, light energy density, humidity and oxygen concentration to get the best operating condition of the system. The results showed that the degradation effect of ethylene thiol was negative correlated with the discharge of waste gas. When exhaust gas flow was 0.3 L/min, humidity was 45% and oxygen concentration was 30%, ethyl mercaptan has the best degradation effect. The degradation rate of ethylthiol increases gradually with the increase of light energy density. Taking energy consumption into consideration, the best degradation effect of ethyl mercaptan was achieved when the light energy density was controlled at 7 W/cm².Through significant correlation analysis, we found that there was a significant positive correlation between the concentration of ethyl mercaptan, the density of light energy and the degradation efficiency of ethanethiol, while there was a significant negative correlation between the flow rate of exhaust gas and the degradation efficiency of ethanethiol.