Pulsed laser beams with two-dimensional array distribution by binary optical elements was used to modify surface processing for ductile iron. The statistical method of microhardness distribution of modified area was proposed to evaluate reasonably the microhardness distribution character, in which the space is divided into a columns 30 μm×30 μm or 30 μm×50 μm grids in the transect of modified area. The microhardness is tested in the intersections of grids. As a result, the data obtained are processed by math statistical method and drawn the contour map. The application shows that the statistical method for microhardness test could reasonably describe modified layer depth and microhardness distribution in the case of multiphase in comparison with conventional method. On some extent, the statistical method may disclose the relation between laser modifying technology and results.