Large-scale　two-dimensional　air-gap　photonic　crystals　(PhCs)　were　embedded　in　an　n-type　GaN　layer　to　enhance　the　light　emission　of　GaN-based　light-emitting　diodes　(LEDs).　The　embedded-PhCs　were　obtained　through　overgrowth　on　n-GaN　templates,　which　had　air　holes　array　previously　fabricated　by　using　nanosphere　lithography　technology.　The　effects　of　the　distance　D　from　active　region　to　PhCs　on　the　light　extraction　efficiency　(LEE)　of　LEDs　are　investigated　by　experiments　and　finite　difference-time　domain　simulation.　The　PhC　LEDs　with　D　=　2370　nm　showed　an　improved　light　output　power　by　80.8%　on　average　at　forward　current　of　350　mA　without　degradation　of　electrical　performance　compared　to　conventional　LEDs.　It　is　mainly　attributed　to　the　improved　LEE　by　enhancing　the　interaction　of　the　guided　modes　and　the　embedded　air-gap　PhCs.