The invention relates to a double-end range finding method for a single-phase earth fault of an overhead-cable mixed line. The method comprises: according to positive-sequence components of three-phase voltages and currents of a front end and a tail end in a normal condition of an overhead-cable mixed line, non-synchronized angles delta of currents at the two ends of the overhead-cable mixed line are calculated; power frequency components of the three-phase voltages and currents at the front end and the tail end of the overhead-cable mixed line after a single-phase earth fault are extracted by using a differential fourier algorithm; symmetric component conversion is carried out on the power frequency components of the three-phase voltages and currents at the front end and the tail end of the overhead-cable mixed line after the single-phase earth fault to obtain sequence components of the voltages and currents at the front end and the tail end of the overhead-cable mixed line after the single-phase earth fault; a sequence component of the single-phase earth fault current of the overhead-cable mixed line is calculated; and the fault point position is determined based on a one-dimensional iterative searching algorithm. Compared with the prior art, the provided method has characteristics of accurate range finding and high efficiency.