With the flourishing development of the Internet and progress of science and technology, the wireless network technology is growing up rapidly at present. People can make connections through the Internet whenever and wherever possible. Mobile IPv6 is proposed in order to support mobility in IPv6 network, offers safer and more efficient mobile communication service to users than Mobile IPv4. However, it still suffers long delays and high packet losses. In order to enable smooth handovers, many researches in which use buffering and forwarding methods have been proposed. Although these proposals significantly improve handover performances, they suffer from the out-of-order delivery problem. This paper proposes a scheme which integrates multicast technologies with FMIPv6 for improving the handover performance. By switching between unicast addressing mode and multicast addressing mode, and letting the access router of the new network (NAR) join the multicast group in anticipation during handover, correspondent nodes (CNs) can transmit data packets to the new and old networks of mobile nodes (MNs) directly at the same time. It not only averts the out-of-order delivery problem, but also reduces the effect of the Duplicated Address Detection (DAD) time on the service disruption time.