The utility model discloses an automatic control only-key lock core for spring locks, which comprises a lock core, a pressure releaser, and a lock core automatic control system composed of a return spring, a connecting board, a stabilizing support, a link plate, a movable bearing disc, a transmission rod and a check ring, wherein the lock core rod is provided with a keyhole; a long marble near the outer end of a marble groove at the bottom layer in the lock core block has one end penetrating through the lock core block to fit and contact with a short transmission rod; the body of the return spring is sheathed on the excircle of the lock core block; the connecting board is assembled with the link plate and the movable bearing disc, is connected integrally with the bottom of the lock core block via a sink screw, is connected with the stabilizing support via screws and is fit with the stabilizing support via the check ring to be limited. The automatic control only-key lock core can avoid unlocking locks without keys, can automatically reject the unlocking process without keys, and can fit various marble lock components to form different automatic control only-key locks, thereby resolving the problem of prior marble locks such as that thieves can push the marbles in each marble groove in the lock core block without keys and fix the marbles at demanded positions to unlock locks, and realizing high anti-theft effect.