A　technique　for　the　in　situ　growth　of　patterned　graphene　by　CVD　has　been　achieved　directly　on　insulating　substrates　at　800　degrees　C.　The　graphene　growth　is　catalyzed　by　a　Ni-Cu　alloy　sacrificial　layer,　which　integrates　many　advantages　such　as　being　lithography-free,　and　almost　wrinkle-free,　with　a　high　repeatability　and　rapid　growth.　The　etching　method　of　the　metal　sacrificial　layer　is　the　core　of　this　technique,　and　the　mechanism　is　analyzed.　Graphene　has　been　found　to　play　an　important　role　in　accelerating　etching　speeds.　The　Ni-Cu　alloy　exhibits　a　high　catalytic　activity,　and　thus,　high-quality　graphene　can　be　obtained　at　a　lower　temperature.　Moreover,　the　Ni-Cu　layer　accommodates　a　limited　amount　of　carbon　atoms,　which　ensures　a　high　monolayer　ratio　of　the　graphene.　The　carbon　solid　solubility　of　the　alloy　is　calculated　theoretically　and　used　to　explain　the　experimental　findings.　The　method　is　compatible　with　the　current　semiconductor　process　and　is　conducive　to　the　industrialization　of　graphene　devices.