The utility model relates to a labeled secondary cable insulation cap including a housing, a reading dial, an insulating layer and a fastening card board. The housing, the display dial and the insulating layer are sleeved sequentially from outside to inside to form a cylinder shape, and a plurality of through hole windows are spaced axially at a side of the housing. The plurality of through hole windows show a number and a character which are made on the outer wall of the reading dial inside. The number and the character represent a row number and a loop number in sequence. A side at an axial direction of the housing is fixedly equipped with the fastening card board. Two sides of the fastening card board are symmetrically equipped with fastening bolts. According to the utility model, insulating protection is carried out for an exposed electrified cable thread residue by use of an insulation cap instead of an insulation tape; the short circuit grounding and physical shock due to connection with the exposed electrified body can be prevented; the safety of field operation is improved; the labeled secondary cable insulation cap is convenient and simple to use; the working efficiency is improved; and the insulation cap can be reused, thereby reducing usage and consumption of the insulating tape, saving energy and protecting environment.