Abstract: It is through analysis of the characteristics of suspension pipeline crossing and force disiribution that the article introduces such binding condition as fracture toughness, works out an optimized model aiming at being the most economical in construclion cost and a set of programme of optimization common to such type of erossing. The study of some enigeering practices and caleulalions show that 1. the coot of pipeline makes up the most percentage, so ealculation (1) and (2) are of practical significance; 2.brittle fracture is found exe: ting uo influence upon the materials of meduim and low strength; with material strength changing from low to high, the strength binding force is getting less and less, whereas the fracture toughness binding force is getting greater and greater, and therefore, for material of medium and high strength, consideration must be given to strength as well as toughness to keep safety. It concludes that the design calculation after this programme is more accurate, economical than by the current method.