An address distribution method, wherein two Broadband Remote Access Servers (BRAS) which are mutually backup devices respectively occupy part of address resources in a shared address pool, and the method comprises: when detecting a user online, a BRAS selecting an address from a corresponding part of address resources in the shared address pool and distributing the address to the user; and the BRAS sending a notification message to a backup device of the BRAS, and informing the backup device of the address occupied by the user; wherein the method further comprises: formulating address distribution rules respectively for the BRASs which are mutually backup devices, and the address distribution rules defining the address resources distributed to each BRAS; wherein the step of formulating address distribution rules respectively for the BRASs which are mutually backup devices comprises: sequencing the addresses in the shared address pool according to an ascending order from the smallest to the biggest; and defining one BRAS of the BRASs which are mutually backup devices to distribute the addresses for online users under said one BRAS in a forward sequence distribution mode and the other BRAS to distribute the addresses for online users under the other BRAS in a reverse sequence mode. when detecting a user online, a BRAS selecting an address from a corresponding part of address resources in the shared address pool and distributing the address to the user; and the BRAS sending a notification message to a backup device of the BRAS, and informing the backup device of the address occupied by the user; wherein the method further comprises: formulating address distribution rules respectively for the BRASs which are mutually backup devices, and the address distribution rules defining the address resources distributed to each BRAS; wherein the step of formulating address distribution rules respectively for the BRASs which are mutually backup devices comprises: sequencing the addresses in the shared address pool according to an ascending order from the smallest to the biggest; and defining one BRAS of the BRASs which are mutually backup devices to distribute the addresses for online users under said one BRAS in a forward sequence distribution mode and the other BRAS to distribute the addresses for online users under the other BRAS in a reverse sequence mode. formulating address distribution rules respectively for the BRASs which are mutually backup devices, and the address distribution rules defining the address resources distributed to each BRAS; wherein the step of formulating address distribution rules respectively for the BRASs which are mutually backup devices comprises: sequencing the addresses in the shared address pool according to an ascending order from the smallest to the biggest; and defining one BRAS of the BRASs which are mutually backup devices to distribute the addresses for online users under said one BRAS in a forward sequence distribution mode and the other BRAS to distribute the addresses for online users under the other BRAS in a reverse sequence mode. sequencing the addresses in the shared address pool according to an ascending order from the smallest to the biggest; and defining one BRAS of the BRASs which are mutually backup devices to distribute the addresses for online users under said one BRAS in a forward sequence distribution mode and the other BRAS to distribute the addresses for online users under the other BRAS in a reverse sequence mode.