Laser beams with ns pulse width are generally employed as an excitation source in the process of detecting inclusions and elemental segregation on a workpiece surface by microanalysis of the laser-induced breakdown spectroscopy. In addition, the ablation crater interval of laser sampling on the sample surface is generally 20 mu m or more. It is difficult to detect the morphology of inclusions smaller than 50 mu m in diameter and the micro-segregation of elements. However, in this work, when the laser ablation crater is 10 mu m and the sampling resolution of the laser on the sample surface is 5 mu m, the morphology and distribution of spherical inclusions (20-60 mu m) in ductile iron can be detected according to the difference of the Fe spectrum on the Fe matrix and the spheroidal inclusions. Moreover, the distribution of micro-segregation of Mg and Ti elements in ductile iron was also studied.