The magnetic property of edged Fe nanowires and its response to tensile axial strain have been investigated using ab initio spin density-functional theory calculations within the generalized gradient approximation (GGA). We also investigate the effect of wire size on magnetism Magnetic moment is enhanced at the edge of nanowires because the coordination number at the edge is smaller than that of bulk. The smallest nanowire have the highest average magnetic moment because the effect of the edge structure becomes dominant with decreasing nanowire size.