Based on the theory of multifractal, this paper analyzes the characteristics of power trading price in different periods. On the basis of the research of shanxi 2020 spot each time data real-time electricity price, electricity market got all kinds of fractal index, shows that they have the multifractal characteristics of screening system that can reflect the working characteristic of the actual data effectively. According to these different fractal parameters, the short-term marginal electricity price prediction model of different time periods is established, and then the phase space prediction model of time period reconstruction is established to predict the short-term electricity price, which finally provides a better guarantee for market participants and managers to avoid the electricity price risk.