To optimize virtual multicast blocking performance, an efficient algorithm combines light-trail partial path sharing, network traffic grooming, and adaptive modulation technique is proposed, which can simultaneously optimize virtual multicast mapping and light-trail selection. First, the bus architecture of light-trail is used to achieve a more flexible partial path-sharing technology. This technology allows light-trail nodes to time-share resources and transmit data to downstream nodes. Second, considering the shorter signal transmission distance of shared partial paths, an adaptive modulation technology that can flexibly choose modulation schemes based on distance is introduced to improve signal modulation efficiency. Furthermore, the support for partial path sharing greatly expands the solution space of virtual multicast node mapping. Simulation results show that the algorithm integrating adaptive modulation and any-node sharing performs the best among comparasion schemes. The improvement of adaptive modulation technique in blocking performance is particularly significant when virtual nodes have more physical node mapping options.