The invention discloses a power overhead line phase checking method and belongs to the electric power system field. With the power overhead line phase checking method adopted, the technical problems of the personal risk of an operator and high possibility of being broken through and damaged of an operation instrument in the high-induced electromotive force environment of lines in the prior art can be solved. According to the power overhead line phase checking method of the invention, a capacitive voltage dividing method is adopted to measure the voltage of one end of a line, and a technical means of grounding a detection phase end and observing the change of the voltage is adopted, so that whether the two ends belong to the same phase is judged; and if the voltage is decreased, it is indicated that the two ends belong to the same phase, if the voltage is not decreased, the two ends do not belong to the same phase. The technical means is safe, convenient, efficient, time-saving and labor-saving. With the technical means adopted, the technical problems of risks brought to the operator and the instrument in the prior art can be well solved, and the technical task of power overhead line phase detection can be completed.