The invention discloses a method for manufacturing a nano all-plastic LED lamp tube. The method comprises a lamp tube shell manufacturing method and a lampshade manufacturing method, wherein the lamp tube shell manufacturing method comprises the following steps: placing plastic used for manufacturing a shell in a charging barrel of an injection molding machine to be molten, then adding glass fibers into the molten plastic material, uniformly stirring with a screw rod, injecting with high pressure into a mold, and conducting cooling solidification and heat treatment to obtain the lamp tube shell; and the lampshade manufacturing method comprises the following steps: placing plastic used for manufacturing a lampshade into a charging barrel of an injection molding machine, heating to the melting temperature, cleaning impurities on the surface of the molten plastic material, then adding nanoscale diffusion powder and a foaming material into the molten plastic material, uniformly stirring with a screw rod, injecting with high pressure into a mold, and conducting cooling solidification and heat treatment to obtain the lampshade. The lamp tube shell manufactured by the method is high in strength, the lampshade has excellent light transmission performance, and the light irradiation range is expanded.