The invention discloses a lock plug structure with an AB key function. The lock plug structure comprises a lock shell, an extractor and a lock cylinder, wherein the lock cylinder is arranged in the lock shell and the extractor in a penetrating mode; a first containing groove for containing a locking assembly and a second containing groove for containing a main locking pin are arranged on the lockcylinder, a third containing groove is formed in the end, away from a key inlet, of the first containing groove, and an auxiliary locking pin is arranged in the third containing groove; and a self-destruction pin connected with the third containing groove in a clamped mode and a first matching part matched with the lock shell are fixed on the auxiliary locking pin, a second matching part matched with the first matching part is arranged in the lock shell, and the auxiliary locking pin is locked in an unlocking state by the self-destruction pin. Through the arrangement, a user can normally unlock a lock using a B key which is not match with a bit of the auxiliary locking pin during decoration, and once a key matched with the bit of the auxiliary locking pin is used, then the key which is notmatched with the bit of the auxiliary locking pin can not unlock the lock, so that the safety is high.