The invention relates to the technical field of relay protection of electric power systems, in particular to a traveling wave ranging method and device in homologous double sampling modes. The methodcomprises the following steps of sampling the homologous traveling wave data in two ways to obtain first sampling data and second sampling data respectively, wherein the amplification factor of the first sampling data is smaller than that of the second sampling data, and appropriate data is selected according to the size of a mutation magnitude for searching the traveling wave head; the first sampling data with the relatively small amplification factor is selected for wave head searching when the mutation magnitude is relatively large, so that the misjudgment on the traveling wave is reduced;the second sampling data with the relatively large amplification factor is selected for carrying out wave head searching when the mutation magnitude is relatively small, so that the leakage judgment of the traveling wave is reduced, and the identification capability and accuracy of ranging are improved.