This study presents an experimental method of determining a two-dimensional image of the gas temperature in atmospheric DC glow corona by spectral imaging. A steady-state glow corona discharge as a partial discharge was generated by applying positive DC voltage to rod-to-plane electrode in synthetic air (N2:79%, O2:21%) at atmospheric pressure. Spectral imaging displays an image, and measures its specific spectra at each pixel in the image. The spectral images were taken by an Intensified CCD camera (ICCD) with ultra-narrow band-pass filters, corresponding to head and tail of nitrogen second positive system band (0−2) (2P(0−2)). The gas temperature was estimated from the emission intensity ratio between the head and tail of 2P(0−2). In this result, the change in the distribution of gas temperature in a positive DC glow discharge due to the amplitude of applied voltage was clearly visualized by spectral image processing.