A method is proposed for calculating the radially distributed emission coefficients of arc plasmas from the projections. The reconstruction is implemented by using a simple and accurate discrete Abel inversion method which is based on Bockasten’s polynomial spline technique. The collected data are filtered in the frequency domain with a lowpass filter to reduce the noise, followed by interpolation for avoiding problems caused by undersampling and increasing data space resolution, and symmetrization for obtaining more accurate results. The arc temperature distribution deduced by the algorithm shows that for a 200 A, 5 mm argon arc, the highest temperature near the cathode is more than 22000 K, which agrees well with results of other researches. This algorithm effectively reduces the influence of noises, and it is very steady and fast, which makes advantages in the processing of large amounts of data.