A vacuum sealing machine capable of locking cover automatically having upper cover limiting mechanism includes an upper lid, a lower seat, and an evacuation tank. The upper lid is hinged to the lower seat. The evacuation tank is located at the front of the vacuum sealing machine, and includes a lid-locking mechanism and an upper lid-limiting mechanism. The lid-locking mechanism is installed on the upper lid or the lower seat, and is connected to the upper lid-limiting mechanism. The upper lid-limiting mechanism includes a limiting lock plate and a limiting buckle portion. The limiting lock plate movably installed on the upper lid is fitted with the buckle of the limiting buckle portion installed on the lower seat; alternatively, the limiting lock plate movably installed on the lower seat is fitted with the buckle of the limiting buckle portion installed on the upper lid.