A simple overlapping nanoparticle method based on fibre oriented capillary flow for depositing Graphene nanoplatelets (GNPs) onto electrically insulting glass fibre surface to form an continuous electrically conducting skin. The multilayer architecture makes the GNP-glass fibre show structure colour. By integrating the optic performance and piezoresistive behaviour, the GNP-glass fibre embedded in epoxy matrix realise the in-situ sensing mechanical deformation of composite. Furthermore, both the structure colour tuning and the resistance changing with the loading strain clearly indicate that the damage is accumulated along the interphase until a catastrophic failure of composites.