1. A system for stateless automatic configuration of an IPv6 address, the system comprising a data card and a terminal, wherein the data card is configured to set and store its own IPv6 address configuration way according to an IPv6 address allocation strategy of a current network, determine the set IPv6 address allocation way after successful establishment of an IPv6 dialup connection and reception of a router advertisement request message transmitted by the terminal for acquiring a prefix address, and when the set IPv6 address allocation way is determined as a static configuration way, discard a router advertisement response message and report a valid IPv6 global unicast address to the terminal; and the terminal is configured to, after successful establishment of the IPv6 dialup connection, transmit a router advertisement request message for acquiring a prefix address to the data card and receive a valid IPv6 global unicast address reported by the data card.