Provided is a composite honeycomb sandwich board and a method for preparing the same. The composite honeycomb sandwich board includes: acore layer, in a honeycomb structure, having upper and lower surfaces, and made of aluminum; and an outer layer, combined at at least one of the upper and lower surfaces and made of an epoxy resin reinforcing material. The epoxy resin reinforcing material is constituted with a reinforcing material and an epoxy resin composition. The epoxy resin composition includes an epoxy resin, a latent curing agent, an accelerator, a coupling agent, and optionally a toughening agent and a filler. The coupling agent includes an amido-containing silane coupling agent.