The present invention discloses a method and router for optimizing a group management protocol so as to reduce the complexity in setting and switching filter modes in the prior protocols. The method includes: a group member sends a membership report to a multicast router; upon reception of the membership report, the multicast router judges whether the report carries an EXCLUDE mode non-empty source list; if so, the router updates a corresponding state inside the router according to a non-source-specific join; or else, the router updates the corresponding state inside the router directly with the information of the report. The method provided by the present invention can avoid the complex switching and processing of filter modes in the prior protocols.