The invention provides a fully-automatic steam sterilizer with a double-interlocking function, and relates to the sterilizing field of medical apparatus and instruments. The fully-automatic steam sterilizer with the double-interlocking function comprises a sterilizer body; a placing cavity is formed on the top of the sterilizer body; a cover plate is fixedly mounted on the top of the sterilizer body; outer locking mechanisms are arranged on the two sides of the sterilizer body; inserting grooves are formed in the positions, on the two sides of the placing cavity, of the top of the sterilizer body; the two ends of the bottom of the cover plate are fixedly connected with inserting rods; and the bottoms of the inserting rods are inserted into the inserting grooves. The fully-automatic steam sterilizer with the double-interlocking function avoids the phenomenon that the locking strength of the cover plate and the sterilizer body is lowered due to the frequent assembling and disassembling condition of the cover plate and the sterilizer body, further achieves the double-interlocking function, guarantees the sealing performance of the fully-automatic steam sterilizer, reduces the operation of maintenance workers, and is high in adaptability and high in reliability.