Multimedia applications have been desirable and attract a rapidly increasing number of network subscribers. However, their generated enormous amount of Internet traffic usually congests the network to cause the degradation of network utilization. Although multicast provides an efficient way for distributing multimedia information to a set of destinations simultaneously, the congestion still degrades the desired QoS (quality of service) of the on-going multicast connections especially if the group of multicast destinations is large and scattered. Hence, this paper proposes a novel adaptive multicast routing (AMRST) approach for satellite-terrestrial network (ST network) to provide reliable and adaptive multicast services to global subscribers. This approach decomposes the multicast delivery problem into two parts, (1) the construction of the multicast tree and (2) the maintenance of dynamic membership. The virtual hierarchical routing tree (VHRT) is proposed for constructing an efficient multicast tree and the re-routing scheme is for maintaining the multicast tree in an optimal routing cost once the membership, such as member joining or leaving, changes dynamically. The AMRST not only keeps the benefits of the traditional terrestrial multicast but also further promotes the multicasting performance by employing the satellite broadcasting capability. The simulation results demonstrate that the AMRST has excellent performance for the satellite-terrestrial network.