In order to improve the electromagnetic shielding performance of a high transparency metallic mesh and to enhance its environment resistance, some experiments of electroless Ni plating on a thin copper mesh with a 9 μm line width, 0.3 μm thickness and 400 μm×400μm period were carried out. Firstly, a sample of thin copper mesh on a K9 substrate was fabricated by the processes of coating photoresist, laser direct writing, developing, vacuum coating and removing photoresist. Then, the sample was cleaned by the supersonic wave, and was immersed about 10 s to 15 s by a 10% hydrochloric acid solution to activate the copper. After that, the sample was immersed again by an electroless nickel plating solution prepared according to a standard, and was maintained about 40 min to 60 min on a constant temperature condition of 85 ℃. Finally, the sample was taken out from the solution, and was baked by a cabinet drier. Experimental results indicate that the coating is homogeneous and strong joined,and the average electromagnetic shield effectiveness of the mesh is approximately 32 dBm when it is tested by a coaxial test method, which has increased by 11 dBm as compared with that test value before nickel-plating.Furthermore, the optical transmission of the mesh reduces less than 1％from 400 nm to 800 nm after nickel-plating. It is concluded that the nickel can be plated for a thin copper mesh, and can increase fairly the electromagnetic shielding effectiveness of the mesh without effect on the optical transmission.