The invention provides an auxiliary cable placing device for power supply construction, which belongs to the technical field of power supply construction auxiliary equipment. The auxiliary cable placing device comprises a cable placing rod used for placing a cable roll. The cable placing rod comprises a first rod body and a second rod body which is coaxially arranged with the first rod body. A receiving cavity for storing the second rod body is arranged in the first rod body. The second rod body is connected with the inner wall of the storage cavity in a sliding mechanism through a support frame arranged at the end part of the second rod body. The auxiliary cable placing device also comprises two mounting bases that are detachably arranged on the moveable end of the first rod body and themoveable end of the second rod body. The first rod body and the second rod body are covered by with a rotating sleeve respectively, and the cable winding is sleeved outside the rotating sleeve. Further, the wheels are arranged at the bottom of the mounting bases. The auxiliary cable placing device for power supply construction aims at solving the technical problem that at least two people are needed to work out when two cables are required to be laid at the same time.