Abstract: Because of the complex mechanism of active faults and their scrambling spread, it is difficult to evaluate the activity of fault system and get satisfied results by traditional methods. Using the theory of fractal can quantitatively analyze and evaluate the fault systems. The fractal dimension of a faults system shows the number of faults in a system, the size of the fault system, the combination mode of the fault system and the dynamics mechanism of the system. So, the fractal dimension can indicate the active and complex grade of a fault system. This paper uses fractal to analyze the faults in Hebei Plain. It gets the fractal dimension of the NNE faults is 1.358. The fractal dimension of the direction of latitude is 1.183. The high fractal dimension is consistent with many existing earthquakes and geological hazards occurred in the plain. At last, the paper analyzes and compares the earthquakes and fractal in the three zones: Hebei plain, Weihe basin and Chuandian zone. It is found that for the relationship between the earthquake spatial distribution and the fractal dimension, the fractal dimension in Hebei plain is the least one, and the earthquake zone is distributed along the NNE in Hebei plain.