Fabrication method of GaN power LED with electrodes formed by composite optical coatings, comprising epitaxially growing N—GaN, active, and P—GaN layers successively on a substrate; depositing a mask layer thereon; coating the mask layer with photoresist; etching the mask layer into an N—GaN electrode pattern; etching through that electrode pattern to form an N—GaN electrode region; removing the mask layer and cleaning; forming a transparent, electrically conductive film simultaneously on the P—GaN and N—GaN layers; forming P—GaN and N—GaN transparent, electrically conductive electrodes by lift-off; forming bonding pad pattern for the P—GaN and N—GaN electrodes by photolithography process; simultaneously forming thereon bonding pad regions for the P—GaN and N—GaN electrodes by stepped electron beam evaporation; forming an antireflection film pattern by photolithography process; forming an antireflection film; thinning and polishing the backside of the substrate, then forming a reflector thereon; and completing the process after scribing, packaging and testing.