Vertical graphene edge is easy to adsorb gas molecules which affects the stability of field emission. The graphene was transferred to insulation wall structure to get the graphene-angle. The insulation wall structure is made on silicon substrate by inductively coupled plasma etching and the method of wet etching, field emission test was made with graphene-angle as field emission tips, and the field emission characteristics of the graphene-angle and the influence of conductive flow on the field emission were studied. The results show that field emission open field strength of graphene-angle is 9.6 V/μm. Under the anode voltage 2 000 V, when the bias voltage applied on the both sides of the graphene-angle increases from 0 V to 10 V, the field emission current increases from 4.5 μA to 15 μA.