An three-dimensional FE model of threaded connection is proposed by means of the general purpose program ANSYS. The model is accurately constructed according to the helical thread profiles. The mechanical behavior of each bolt subjected to eccentrically loading is investigated and the stress distribution is discussed detailedly. Based on the stress level, the fatigue life of threaded connection is predicted by the cumulative damage method. This work can provide a deeply understanding on the mechanics behavior of bolt connection in engineering, especially for its application on the appending equipments of airplane.