The invention discloses an anti-drop mechanical lock for a lift-sliding garage. Anti-drop device holes are formed in the two ends of each car carrying board beam respectively, an anti-drop mechanical lock structure is arranged in each hole, and each anti-drop mechanical lock structure comprises a hanging rod, a support top tongue bolt, a support top tongue, a hanging sleeve and a top block, wherein the support top tongue bolt is embedded in one end of the hanging rod, the support top tongue is connected to the support top tongue, the hanging sleeve is connected to the outer side of the support top tongue in a sleeving mode, and the hanging sleeve is internally provided with the top block. Accordingly, by arranging a drooping lock on a longitudinal beam, a mechanical lock tongue is installed on the lock; a lock sleeve is arranged on a car carrying board, by means of up-down movement of the car carrying board, the lock tongue on the lock can make the lock sleeve get away from the lock as needed, or clamp the lock sleeve and the lock, and the car carrying board is prevented from dropping.