A method and system for reducing changes in a designated router (DR) of a protocol independent multicast (PIM) protocol are disclosed. The method includes: after a PIM device joins a shared network, an interface of the PIM device receiving a Hello message sent by other PIM device in the shared network, wherein the Hello message carries a DR address option; and the interface of the PIM device using a currently used DR address carried in the Hello message as a DR address of the interface.