A method for transferring authorization information, a relay device, and a server are provided. The method includes: receiving, by a DHCPv6 relay device, authorization information delivered by an AAA server; and inserting an option into a DHCPv6 Relay-Forward message, encapsulating the authorization information in the option, and sending the option to a DHCPv6 server. By using the technical solutions of the present application, a DHCPv6 relay device sends authorization information delivered by an AAA server to a DHCPv6 server, so that the DHCPv6 server can provide a correct configuration for a DHCPv6 client according to the authorization information delivered by the AAA server.