Abstract: Negative electricity price is a new phenomenon that occurs in power systems with a high proportion of renewable energy. Focusing on the phenomenon of long-time-scale negative electricity prices in the Shandong electricity spot market of China during the “May Day” holiday, considering the operation characteristics of Shandong power system of China, market clearing and pricing models, the formation mechanism of negative electricity prices, as well as the impact of the negative electricity price on the benefits and electricity purchasing costs of coal-fired power units, renewable energy, and power consumers, are comprehensively analyzed from the various factors such as supply-demand relation, participants, bidding. The analysis results show that the long-time-scale negative electricity price in Shandong province of China reflects the relationship of whole supply exceeding demand and the impact of renewable energy consumption demand on the market price. At the same time, in conjunction with the medium-and long-term contract for difference mechanism, the negative electricity price has a limited impact on the economic benefits of the market participants on both power generation and consumption sides. On this basis, some relevant suggestions are put forward to improve the design of electricity market mechanisms.