The invention discloses an electromobile battery box and a locking mechanism thereof. The locking mechanism comprises a lock head, a lock sleeve is mounted axially in an inner hole of the lock head in an inserted manner, press-type self-locking units are uniformly distributed along the circumferential direction of the lock head between the lock sleeve and the lock head, each self-locking unit comprises a control shaft connected on the front end face of the lock head in an axial limiting moving inserted manner, and a stopper assembled between the control shaft and the lock sleeve, a locking recessed portion allowing the corresponding end portion of the stopper to be clamped in and mounted between the lock sleeve and the control shaft in an ejected manner to realize locking of the lock head when the control shaft moves forwards to a locking position is arranged on the peripheral face of the lock sleeve, an unlocking groove allowing the corresponding end portion of the stopper to enter to enable the stopper to be capable of being radially separated from the locking recessed portion when the control shaft moves backwards to an unlocking position is formed on the peripheral face of the control shaft, and a resetting elastic member applying a forward acting force on the control shaft to prevent the same to be unlocked is arranged between the control shaft and the lock head. The locking mechanism and the electromobile battery box using the same have the advantages of convenience in operation and stable locking effect.