The utility model provides a step insulating fixing part is used to a multistage voltage -sharing shielding section of thick bamboo for inside the pot -type capacitance type potential transformer, a shielding section of thick bamboo is used in the fixed and inside multistage voltage -sharing of support condenser, and insulating fixing part divide into the first half and the latter half, and the first half and the latter half are multistage stair structure. Adopt this embodiment's insulating fixing part, the simple relatively and installation of being convenient for of structure, the insulating fixing part of this kind of structure of while is because whole cover is outside at a shielding section of thick bamboo to do not influence the coupling capacitance between the shielding section of thick bamboo, in other words, compromise mechanical strength and insulating requirement.