When single-line-to-ground fault happen in neutral non-effectively earthed system, there is a big difference between the fault feeder and un-fault feeder in transient signal energy centralized frequency band and signal amplitude of fault phase. The transient signal energy in fault feeder’s fault phase is bigger, and it centralizes in lower frequency band. But the transient signal in un-fault feeders’ has the contrary features. And this feature is affected little by the fault initial angle. So the paper proposed a method that using the gravity frequency and transient signal energy to form a two-dimension line selection method that using the signal overall distribution characteristics. It can be applied in neutral unearthed and resonant system simultaneously. And the method is effectively to different fault initial angle and fault resistance. The method is proved correctly, effectively and adaptively by actual simulation in different fault cases.