Based　on　the　application　of　etching　of　GaAs-based　photonic　crystals　to　photonic　crystals　vertical　cavity　surface　emitting　laser,　the　characteristics　of　photoresist　and　SiO2　masks　were　studied　and　their　impact　on　the　effect　of　ICP　etched　on　GaAs-based　two-dimensional　photonic　crystals　was　explored.　Reasons　for　accidented　flat,　bad　vertical　degree　and　coarse　sidewall　were　analyzed　when　small　size　photonic　crystals　were　etched.　Finally,　by　modification　of　the　fabrication　conditions,　high　quality　photonic　crystals　with　smooth　and　vertical　sidewall　and　flat　bottom　were　achieved　with　BP212-7CP　photoresist　as　mask.　The　diameter　of　the　photonic　crystals　is　1.2-4.0　μm　and　the　depth　of　photonic　crystals　is　1.5　μm.