Abstract: The paper is concerned with the slip line field for bending of a bar with the deep wedge shaped notches.Along its boundary slip line of deforming region,the parametere s and t are intruduced and then the position of disconti nuity point c and the lim it bending mo-ment were calculated using integration depending on a parameter,The results of the meth-od are the same with the conventional solution from the reference in this paper. The paper is instructed by professor Zhamg Qiang.