Abstract: In this paper a method to process the arc spectrum data in a real SF6 circuit breaker was described and the arc temperature characteristics were analyzed. Considering the fact that there were few sampling points for actual measurement in a real SF6 circuit breaker, the algorithm based on cubic spline interpolation with an accuracy of 0.85% was applied. The arc spectrum data was corrected based on the principle of line broaden to correct noise and spectral shifts. The radial distribution of arc temperature was calculated. The arc temperature after zero crossing and the arc temperature at different current and position were analyzed. Temperatures in the arc center were in the range of 15000K-25000K while the arc circuit varied from 6kA-30kA. Using the data processing method in this paper, the accuracy of arc temperatures is 7.08%.