A method for implementing secure call forwarding, characterized by comprising: a calling party calling a called party, and the called party triggering a subscribed call forwarding service (401-409, 501-509 and 701-709); a key management server obtaining information of a legal call-forwarded party of the called party through an application server; the call-forwarded party obtaining a media key from the key management server; and the calling party establishing a call connection with the call-forwarded party (417, 517, and 617 and 717); wherein the step of the key management server obtaining information of a legal call-forwarded party of the called party through an application server comprises: the application server including encrypted binding relation information of the called party and the call-forwarded party in a call request message and sending the call request message to the call-forwarded party; and the key management server judging whether the call-forwarded party is a legal call-forwarded party of the called party according to a message including the encrypted binding relation information sent by the call-forwarded party (410-412,510-512 and 610-612); or the application server judging whether the call-forwarded party is a legal call-forwarded party of the called party according to information of the called party and the call-forwarded party provided by the key management server, and feeding a judging result back to the key management server; or the application server returning a call forwarding user identifier list of the called party to the key management server according to information of the called party provided by the key management server; and the key management server judging whether the call-forwarded party is a legal call-forwarded party of the called party according to the call forwarding user identifier list of the called party. a calling party calling a called party, and the called party triggering a subscribed call forwarding service (401-409, 501-509 and 701-709); a key management server obtaining information of a legal call-forwarded party of the called party through an application server; the call-forwarded party obtaining a media key from the key management server; and the calling party establishing a call connection with the call-forwarded party (417, 517, and 617 and 717); wherein the step of the key management server obtaining information of a legal call-forwarded party of the called party through an application server comprises: the application server including encrypted binding relation information of the called party and the call-forwarded party in a call request message and sending the call request message to the call-forwarded party; and the key management server judging whether the call-forwarded party is a legal call-forwarded party of the called party according to a message including the encrypted binding relation information sent by the call-forwarded party (410-412,510-512 and 610-612); or the application server judging whether the call-forwarded party is a legal call-forwarded party of the called party according to information of the called party and the call-forwarded party provided by the key management server, and feeding a judging result back to the key management server; or the application server returning a call forwarding user identifier list of the called party to the key management server according to information of the called party provided by the key management server; and the key management server judging whether the call-forwarded party is a legal call-forwarded party of the called party according to the call forwarding user identifier list of the called party. the application server including encrypted binding relation information of the called party and the call-forwarded party in a call request message and sending the call request message to the call-forwarded party; and the key management server judging whether the call-forwarded party is a legal call-forwarded party of the called party according to a message including the encrypted binding relation information sent by the call-forwarded party (410-412,510-512 and 610-612); or the application server judging whether the call-forwarded party is a legal call-forwarded party of the called party according to information of the called party and the call-forwarded party provided by the key management server, and feeding a judging result back to the key management server; or the application server returning a call forwarding user identifier list of the called party to the key management server according to information of the called party provided by the key management server; and the key management server judging whether the call-forwarded party is a legal call-forwarded party of the called party according to the call forwarding user identifier list of the called party.