The invention relates to a lock assembly for a battery lock-up mechanism, a power battery comprising the lock assembly, a battery lock-up mechanism, a new energy vehicle, and a method for installing/detaching a power battery onto/from a new energy vehicle by using the battery lock-up mechanism of the invention. The lock assembly for battery lock-up mechanism comprises a casing and an stop end plate which define an accommodation space, in which a central pull shaft, an adjustment block and a return spring or the like are disposed. The return spring is sleeved over the central pull shaft. The technical solutions of the invention have a low cost, are easy to operate and are stable and reliable.