Abstract: The present application discloses a locking device comprising: a housing; a plunger inserted into the housing, movable and rotatable to transit between a locking position and an unlocking position, wherein when the plunger is in the unlocking position, the plunger is in a first rotating position and a first axial position, when the plunger is in the locking position, the plunger is in a second rotational position and a second axial position; a rotor accommodated in the housing and rotatable around a rotor rotation axis relative to the plunger between a engaged position and a disengaged position, wherein when the plunger is in the locking position, the rotor is rotatable to the engaged position to prevent the plunger from moving; and a motor accommodated in the housing and configured to drive the rotor to rotate. The present application further discloses a locking system.