Abstract: In order to optimize the cost of multicast tree, minimize the joined latency, and reduce the transmission delay in mobile and wireless environment, bone node set is introduced to group communication for mobile IP. Based on the idea of bone node set, a multicast routing algorithm called BNSBMR （bone node set-based multicast routing algorithm） is designed in this paper. Bone node set is a dynamic set of mobile IP AR （access router） which satisfies some special conditions. BNSBMR can efficiently construct a series of multicast trees for mobile IP and characters itself in three aspects. Firstly, it optimizes the cost of multicast tree and reduces the bandwidth consumption by using bone node set. Secondly, it reduces the joined latency for mobile node to join multicast session, which is helpful to achieve a fast handover. Thirdly, the transmission delay for multicast packet is lessened by sharing those bone nodes. Correctness of BNSBMR is proved and the time complexity is analyzed in theories. Simulation experiments are designed based on a 5×5 mesh topology. Those results show that BNSBMR has optimized cost of multicast tree, reduced the joined latency and minimized the transmission delay. QoS （quality of service） of multicast routing for mobile IP is improved by using bone node set in some degree.