The two problems restrict the development of directly buried pipeline installation without compensation technology in the heating engineering.Therefore, the intensity of elbow itself is analyzed to optimize the elbow .A new model of elbow is provided .This paper uses ANSYS finite element analysis software to establish a new type of elbow model.We compare and analyze the stress of ordinary elbow which add block and do not add block ; two different types which both have the same wall thickness and new type elbow which have 5 different wall thickness for each elbow.The results show that:(1) the new type elbow can reduce the stress greatly;(2) with the increasing diameter of elbow, the stress of inner elbow decreases gradually. Therefore, this new type of elbow can truly realize non-compensating installation in heating system.