Disclosed is a substation intrusion overvoltage detection method. The method adopts a Rogowski Coil for measuring a leakage current signal of a substation line spaced arrester; when the leakage current signal contains a high-frequency transient signal in addition to a 50Hz power frequency signal, adopts a band-stop filter for filtering a power frequency component in a frequency domain, while retaining and re-constructing the high-frequency transient component in a time domain to obtain a high-frequency transient current time domain signal, that is a discharge current released when the arrester is subjected to the intrusion of overvoltage; and then substitutes the amplitude of the high-frequency transient discharge current into a volt-ampere characteristic curve of the arrester, and calculates the amplitude of the intruded overvoltage.