[en] A new edge tangential multi-energy soft x-ray (ME-SXR) diagnostic with high temporal (≤ 0.1 ms) and spatial (∼1 cm) resolution has been developed for a variety of physics topics studies in the EAST tokamak plasma. The fast edge electron temperature profile (approximately from $r/a\sim <!--\; ???\; -->0.6$ to the scrape-off layer) is investigated using ME-SXR diagnostic system. The data process was performed by the ideal ‘multi-foil’ technique, with no priori assumptions of plasma profiles. Reconstructed ME-SXR emissivity profiles for a variety of EAST experimental scenarios are presented here for the first time. The applications of the ME-SXR for study of the effects of resonant magnetic perturbation on edge localized modes and the first time neon radiating divertor experiment in EAST are also presented in this work. It has been found that neon impurity can suppress the 2/1 tearing mode and trigger a 3/1 MHD mode. (paper)