Along with the comprehensive transformation of China’s economy and the steady progress of the electricity system reform, the market mechanism will play an increasingly important role in the optimal allocation of resources. How to further stimulate market vitality and continue to promote the process of electricity market is a challenge for the power trading center. The operation of the market in recent years by constructing a market index is analysed. Firstly, the current situation of electricity market development in the domestic spot pilot and the main changes in the electricity trading rules in Beijing are summarized, and the impact of the re-form of the trading rules from the policy level is analysed. Then, the compilation methods and applications of market composite indices is analyed and three indices applicable to the evaluation of the electricity market trading are proposed in Beijing. Finally, the market transaction index is used to analyse the case, to verify the rationality of the index on the one hand, and to argue for the promotion of the reform of the electricity market on the other.