The invention relates to a room-temperature curing epoxy structural adhesive composition, which comprises a component A and a component B, wherein the component A comprises bisphenol A epoxy resin, toughness modified bisphenol A epoxy resin, silane coupling agent, thixotropic agent and colorant; and the component B comprises polyamide, polyether amine, a filler and a curing accelerator; the toughness modified bisphenol A epoxy resin is liquid nitrile rubber-modified bisphenol A epoxy resin and / or polymer-toughened bisphenol A epoxy resin with a nuclear shell structure; meanwhile, the invention also provides a method for preparing the room-temperature curing epoxy structural adhesive compositiion. The structural adhesive of the invention has the advantages of good toughness, strong high-temperature strength, short curing time, simple preparation method, and the like.