Abstract: Analyzed with the FE model are the structure,sealing and fatigue resistance of the premium connection under bend load. And relevant evaluation methods are detailed. It is regarded via the analysis that there exist difference between the stress statuses of the premium connection under bend load in different positions;along with increase of the bend degree,the sealing strength of the tensile face side is decreased,whereas that of the compression face side is increased;and the most dangerous location of the said premium connection where fatigue damage is very possible to take place is the oil groove of the coupling.