Using　the　plasma-enhanced　chemical　vapor　deposition　method,　we　grow　vertical　graphene　thin　films　onto　SiO2/Si　substrates,　which　is　a　special　format　of　graphene　composed　of　numerous　macroscopically　uniformly　distributed　graphene　flakes　approximately　vertically　arranged.　The　growth　parameters,　including　the　growth　temperature,　growth　time　and　plasma　power,　are　systematically　studied　and　optimized.　Most　importantly,　the　function　of　plasma　has　been　revealed.　In　the　same　deposition　machine,　we　have　altered　the　plasma　electrode　and　heater　configurations,　and　found　that　the　vertical　graphene　can　only　grow　in　local　plasma　environment.　That　is,　the　samples　have　to　be　well　immersed　in　the　plasma　sheath　electric　field.　In　this　way,　the　vertical　growth　of　graphene　and　the　local　enhancement　of　electric　field　can　form　a　positive　feedback　loop,　resulting　in　the　continuous　growth　of　vertical　graphene.　This　experiment　clarifies　the　function　of　plasma　electric　field　in　the　vertical　graphene　growth,　and　can　offer　hints　for　the　growth　of　other　vertical　two-dimensional　materials　as　well.　The　vertical　graphene　films　are　scalable,　transfer-free　and　lithographically　patternable,　which　is　compatible　with　standard　semiconductor　processing　and　promising　for　optoelectronic　applications.　We　have　characterized　the　optical　properties　of　the　as-grown　vertical　graphene　films,　where　a　nearly　zero　transmittance　is　observed　for　1100-2600nm　wavelengths,　indicating　a　superstrong　absorption　in　the　black　colored　vertical　graphene.