Abstract: The fractal theory provides an important method in study of irregular objects of self-similarity and self-affinity.The fractal dimension is a quantitative parameter that describes the fractal objects and indicates the complicity and essential characteristics of the system.In this paper the phase space of the time series of nature field is reconstructed by the theory of phase space reconstructing and G-P algorithm,the results show that the phase space of nature filed has the chaotic attractor,although the nature field is similarity with random nature signal,it has intrinsic certainty random signal and is likely to chaotic.The results of field data analysis indicate that the correlative dimension of time series of nature field is related to earth medium characteristics intently and qualitative reflect the characteristics of the distribution of electricity and construction of medium.