Network coding was introduced to optimize the selection of multi-core nodes and transmission of multicast information. A method was proposed to construct optical multicast routing based on multi-core node shared tree and network coding to decrease the wavelength consumption and to improve the performance of network load balance. The network coding candicate core node set was produced by deleting the nodes which lead to the source node bypass loop. The network coding core nodes of multi-source shared trees were determined by utilizing the heuristic matrix operation to achieve the minimal core nodes covering the maxmial source nodes. Then, the network coding was applied to transmit the information between the core nodes and destination nodes to reduce the wavelength consumption. And, the wavelength assignment and edge disjoint path were discussed for the multi-core node shared tree. Comparing with the multicast routing with single-core shared trees and singel-core shared trees based on the network coding, the simulation results show that the multicast routing with multi-core node shared trees based on network coding can get the least required wavelenght and achieve the best performance of network load balance.