Abstract: A new characteristic based on phase space theory to identify magnetizing inrush current is introduced.By reconstructing phase space with chaotic time-series,the one-dimensional single current sampled signal is mapped to a hyper-space to become hyperdimensional;meanwhile,the phase locus indicates the difference between inrush current and inner fault current.Simulation results show that it is possible to reconstruct a similar phase space under variable cases,and the phase locus of inrush current is very different from that of inner fault current.