The invention discloses a composite insulator device with a built-in piezo-resistance unit. The composite insulator device comprises the piezo-resistance unit, an insulating pillar, enhanced blowout gap units and installation hardware; the piezo-resistance unit comprises a piezo-resistance subunit core, an insulating core rod and an insulating sheath; each enhanced blowout gap unit comprises a blowout cavity, an insulated support member and a gap electrode; and the enhanced blowout gap units are fixedly installed in the two ends of the insulating pillar or arranged uniformly along the axial direction of the insulating pillar. A lightning arrester is integrated with an insulator, the rated voltage of the piezo-resistance unit is reduced by using the high arc extinguishing capability of theenhanced blowout gap unit, and the device is mini, light and cheap; and the device is assembled while leaving the factory, onsite part adjustment and assembly are not needed, it is not required to strip an insulating layer of a lead when the device is connected with the insulating lead, and installation and construction are simple convenient.