The present invention discloses a digital cryptographic key protecting method, which comprises that a server encrypts to the original cryptographic key with a receiver public cryptographic key according to the encryption algorithm, to span the encryption cryptographic key messages, a data packet is formed with the encryption cryptographic key messages and other cryptographic key related messages, a signing operation to the data packet is performed with a server private cryptographic key to span the signing messages, the data packet and the signing messages is sent to the receiver, the receiver processes the other related messages of the cryptographic key in the data packet according to the first message-digest Algorithm, to span a message-digest value which acts as a scrambling cryptographic key to encrypt to the original cryptographic key, thus a storage encryption cryptographic key is obtained, and the storage encryption cryptographic key, the related messages of the original cryptographic key and the scrambling algorithm are stored in a data base, the client end sends a cryptographic key requirement to the receiver, the receiver encrypts again to the storage cryptographic key after the storage cryptographic key is taken out, and sends the results to the client end and takes out the messages in the data base regularly, and update the scrambling algorithm and the message-digest and the storage encryption cryptographic key. The present invention improves the security of the cryptographic key input, storage, output and updating on the cryptographic key management convenience guaranteeing.