In　this　paper,　we　propose　a　scheme　to　show　signatures　of　multipartite　optomechanical　entanglement,　which　is　based　on　two　high　quality　factor　(high-　Q)　silicon　nitride　(Si3N4)　microdisk　cavities　coupled　to　a　nanostring　waveguide　via　evanescent　field.　Genuine　tripartite　optomechanical　entanglement　is　shared　in　the　subsystem　even　though　the　two　fields　of　microdisk　cavities　do　not　have　direct　interaction.　In　addition,　we　study　the　behaviors　of　the　bipartite　entanglement　between　the　pairs　of　the　system　constituents　by　numerical　simulation.　©　2013　Springer　Science+Business　Media　New　York.