A method and system for establishing an optimized path for multicast data. The method includes: establishing a multicast tunnel between a mobile access gateway (MAG) to which a multicast receiving end (MN) belongs and a mobile access gateway (MAG) to which a multicast source (MN-S) belongs, and after receiving a multicast message sent from the MAG to which the MN-S belongs, sending the multicast message to the MAG to which the MN belongs via the multicast tunnel. The method for establishing an SPT path provided by the present solution can improve the routing efficiency and mobile multicast performance.