By mildly oxidizing Cu foil and slowing down the total gas flow rate, we develop an easily repeatable atmospheric growth method to grow single-crystal graphene of centimeter-size. The graphene edge, which is different from the previously reported straight edge, is connected by a series of graphene-corners. The graphene-corner, ranging between 100째 and 110째, is formed by a zig-zag edge and a mix edge. The oxidation of Cu crystal boundaries results in the rearrangement of active Cu sites for graphene nucleation, thus suppressing graphene nucleation density.