The invention discloses a three-phase electric zero sequence current transformer for preventing a cable from loosening. The three-phase electric zero sequence current transformer comprises a jacking bolt, a core tube, a current transformer, a crimping component and a claw pressing component, wherein a radial-guiding slide hole is formed on a tube wall of the core tube; an internal thread area is formed in a tube cavity of the core tube; the crimping component comprises a plurality of crimping parts; each of the crimping parts is provided with a pressing plate part and an anti-loosening connecting part; each of the crimping parts is detachably arranged on the core tube through the anti-loosening connecting part; the claw pressing component comprises a plurality of pressing claws; each of the pressing claws comprises a top plate part, a guiding slide block part and a driving surface; each guiding slide block part is inserted into a corresponding radial guiding slide hole; the jacking bolt comprises a body, an external thread area and a jacking boss; the jacking boss has the shape of a circular cone platform; the external thread area of the jacking bolt is matched with the internal thread area of the core tube; the driving surface of each pressing claw is matched with a peripheral wall of one corresponding jacking boss; a mounting thread hole with a built-in temperature sensor is formed on at least one of the crimping parts. The three-phase electric zero sequence current transformer is firmly, stably and reliably mounted.