In this work, we analyze the X-ray data of supernova remnant (SNR) candidate G278.0+12.4. We examine its nature and the X-ray properties such as electron temperature kTe and abundances, using Suzaku data. We found that the X-ray emission is well represented by two-component model: an absorbed thermal plasma with about 5 keV and non-thermal plasma with a photon index ~ 0.5-1. Our spectral analysis confirms that the G278.0+12.4 is likely to be an SNR. We found non-thermal X-ray emission from the spectra, which indicates that a pulsar wind nebula scenario is possible for G278.0+12.4. In order to make predictions for future missions, we perform XRISM and Athena simulations. We present our results on the nature of G278.0+12.4.