Abstract: For the problem of fatigue life of hydraulic support link in actual practice, the paper that deals with the study of back link of hydraulic shield support derives drawing force, compression force and torque of the link under eccentric loads. On this basis, static strength and fatigue strength of the linik is analysed, while fatigue life nephogram is plotted. Next analysis is about surface finish factor and their the influence on fatigue life. Finally, the paper analyses load sensitivity to fatigue failure. The calculation results show that surface finish factor and torque of the link have obvious effect on fatigue life of it. The research method on fatigue life proposed can provide theoretical basis and be of valuable reference to optimal design, manufacture and maintance of the back link of similar hydraulic support.