The invention discloses a method for evaluating the insulation performance of a power cable in a stage with the voltage being 35kV or below 35kV. The method comprises the steps of determining the power cable which is in need of carrying out insulation performance evaluation and planning to carry out power failure detection on a section of cable circuit by combining with an overhaul plan of electrical devices which are connected with the power cable; disconnecting the section of the cable circuit with the electrical devices at two ends and ensuring a safe distance between the section of the cable circuit and adjacent electrical devices; applying oscillation wave voltage to a tested cable through a dedicated detection device and carrying out local discharge detection on the cable circuit; carrying out system analysis on a local discharge detection result by comparing a cable path and a position laying situation of an intermediate joint; meanwhile, carrying out effective evaluation on the insulation performance of the cable circuit by combining the size and the generation position of local discharge capacity of the cable circuit. According to the method disclosed by the invention, effective evaluation is carried out by carrying out the oscillation wave local discharge detection, safe and reliable running of a power grid is ensured, and the problem that a method for accurately mastering the insulation performance of the power cable in the stage with the voltage being 35kV and below 35kV is lack at present can be better solved.