The traditional multicast service is based on the host group model, which transmits the packets to a set of receivers with a single destination address. In this model, anyone can send or receive the multicast packets once it joins the multicast group. As a result, the multicast service is difficult to deploy due to the lack of effective authentication and accounting mechanisms. The recent development of the new Internet architecture based on the Identifier/Locator Separation mechanisms brings a promising opportunity to improve the multicast service model. In this paper, we propose a Multicast service model based on Identifier/Locator Separation (MILS) mechanism. This model introduces Multicast Service Identifier (MSI) and Multicast Group Identifier (MGI) to identify the multicast membership and the multicast delivery. Besides, it utilizes Multicast Controller (MC) to maintain the mapping between MSI and MGI to provide the authentication and accounting functions, so as to satisfy the different requirements of multicast services. We evaluate its performance by simulations, and analyze its scalability in terms of the group number and session density. The results show that the MILS can reduce the multicast states and improve the performance of multicast services.