Abstract: To optimize the key disciplinary system of China Institute of Atomic Energy (CIAE), and promote the cross-disciplinary integration and interdisciplinary research, the analysis and argumentation on the development of key disciplines in the new era was carried out on the basis of the original “eight-discipline”. The disciplinary development path in CIAE through the past 75 years was systematically analyzed in the paper, which had been characterized by “tasks leading disciplines, disciplines promoting tasks”. The disciplinary system and key development directions of the new “ten-discipline” in the new era were proposed, and the measures to strengthen the construction of disciplinary system were suggested.