The present application relates to the technical field of control, and particularly relates to a method, apparatus, and system for improving memory efficiency. The method comprises: receiving a physiological signal of a user in a state of sleep; according to said user physiological signal, determining whether the user is in a sleep state of a slow-wave sleep phase; if so, then controlling a stimulation apparatus to release preset stimulation information so as to stimulate to an active state the cranial nerves of the user in a sleep state of a slow-wave sleep phase, wherein said preset stimulation information is the same as the stimulation information perceived by the user when in a learning state. The described embodiment more effectively improves the memory efficiency of the user when in a sleep state.