The utility model relates to a test lead with series connection power, including a test lead, tell the access instrument branch that two root structure are the same at the left end of test lead, go into the ramose left side end of instrument at two piece -root graftings and all be equipped with cylindrical joint admittedly, tell two piece -root graftings at the left end of test lead and go into measurement station branch, it has rectangular flat joint to go into the equal rigid coupling in the ramose right side end of measurement station at two piece -root graftings, wherein, has concatenated the 10v power on measurement station branch is gone into to a piece -root grafting, moreover the 10v power is the cuboid dry battery, and the positive negative terminal of dry battery all adopts dry contact signal terminal to arrange the structure. The utility model discloses when the test lead reduces generating set speed control system parameter testing on the conventional tests wire time of series connection power, reduce artifical intensity of labour by a wide margin, shorten working time, improve labor efficiency.