The motphology amount,size and distribution of non-metallic inclusions in highspoed tool steeis M2Al and M2 have ben studyed by oberving the blocksample and electrolytic ex-tracting inclusion powder with quantitative microscope,SEM and chemical analyzing techniques.Itwas shown that the amount,sise and nonuniformity of distribution of inclusions all increase evi-dently because of the addition of aluminum,and the situation is caused mainly by the increase of theamount of Al2O3 inclusion and its composites.