According to the method for preventing IP multicast data stream from overloading the communication system by distinguishing multiple services, when a multicast data packet ‘packet (key)’ with its key value being ‘key’ reaches the forwarding layer, if it doesn't find the matching multicast route entry or matching multicast forwarding entry, and it satisfies the requirement of multicast protocol Assert state machine, then it searches for current-limiting policy list L (type, key) according to the key, and applies the searched current-limiting policy to multicast forwarding and packet up-sending. If it finds the matching multicast route entry and the protocol requests sending the multicast data packet to the protocol processor, the new multicast forwarding entry P_M(key) is formed with the current-limiting policy of distinguishing the service type(key), and P_M(key) is used to forward and up-send. The above-mentioned three current-limiting types may be used separately or combined freely.