A method for intercepting a multicast protocol packet, comprising: acquiring multicast work information of a router, wherein the multicast work information comprises an interval of receiving general query packets, the number of group-specific query packets that are received after a switch forwards a host leave packet to the router, and maximum response time set for a multicast group member host; acquiring a multicast protocol parameter of the switch according to the multicast work information of the router, wherein the multicast protocol parameter comprises an interval of sending general query packets, a robustness variable, and a query response interval; acquiring port aging time of the switch according to the multicast protocol parameter of the switch; and aging a port if no multicast protocol packet is received on the port within the port aging time; wherein, the interval of sending general query packets is estimated according to the interval of receiving general query packets; ports of the switch include a member port and a router port; the acquiring port aging time of the switch comprises: acquiring a product of the interval of sending general query packets and the robustness variable, and using the product plus the query response interval as aging time of a first member port of the switch; and acquiring a product of the interval of sending general query packets and the robustness variable as aging time of a router port of the switch. acquiring multicast work information of a router, wherein the multicast work information comprises an interval of receiving general query packets, the number of group-specific query packets that are received after a switch forwards a host leave packet to the router, and maximum response time set for a multicast group member host; acquiring a multicast protocol parameter of the switch according to the multicast work information of the router, wherein the multicast protocol parameter comprises an interval of sending general query packets, a robustness variable, and a query response interval; acquiring port aging time of the switch according to the multicast protocol parameter of the switch; and aging a port if no multicast protocol packet is received on the port within the port aging time; wherein, the interval of sending general query packets is estimated according to the interval of receiving general query packets; ports of the switch include a member port and a router port; the acquiring port aging time of the switch comprises: acquiring a product of the interval of sending general query packets and the robustness variable, and using the product plus the query response interval as aging time of a first member port of the switch; and acquiring a product of the interval of sending general query packets and the robustness variable as aging time of a router port of the switch. acquiring a product of the interval of sending general query packets and the robustness variable, and using the product plus the query response interval as aging time of a first member port of the switch; and acquiring a product of the interval of sending general query packets and the robustness variable as aging time of a router port of the switch.