The invention relates to a glass fiber reinforced plastic cable channel cover plate and a production method thereof. The cover plate is a rectangular hollow belly structure, longitudinal stiffening ribs are arranged in the hollow belly of the cover plate and the upper surface of the cover plate is provided with strip-shaped antiskid grains; the invention comprises the following raw materials: unsaturated polyester resin, curing agent, packing, polyvinyl alcohol solution, pigment, fiberglass roving and fiberglass felt; the invention comprises the following steps: (1) arranging a tooling equipment on an extrusion molding machine; (2) mixing and pouring the raw materials in a resin tank; and (3) inducing the fiberglass roving and the fiberglass felt through immersion, a performing device, a forming device, curing and cutting. The cover plate has high strength, smooth surface, neat and beautiful appearance, corrosion resistance of alkali, acid, petrol and the like, aging resistance, long service life without pulverization, discoloration, crack, deformation and the like. The invention ensures the safe operation of cables and prolongs the service life of the cables.