Abstract: Because of the deviant fracture on lateral supports of JAT610 loom,the stress of the bar was studied by FEM software ANSYS,combining the stress result of actual measure in facture,the fatigue life of the bar was calculated. The reason that the fatigue life of the bar was too short was found,and the shape was improved to extend the fatigue life. The analysis shows that the stress convergence in high-speed machine would cause the machine fatigue and influence the life of the machine, the decrease of the maximal stress and range of stress in machine can extend the fatigue life of machine availability.