The invention discloses a method for authenticating in end-to-end communications based on a mobile network, applied to a system including a first service entity requesting a service, a second service entity providing the service and an entity authentication centre, EAC; respectively performing a mutual authentication between the first service entity and the EAC and that between the second service entity and the EAC according to the negotiated authentication mode; if the first service entity requests the second service entity to provide the service, the EAC providing authentication inquiring for the first service entity and the second service entity according to the negotiated authentication mode, and generating a shared derived key according to the negotiated authentication mode; and the first service entity and the second service entity authenticating each other according to the shared derived key and the negotiated authentication mode, and generating a session key for protecting the service.