Abstract: A two node cable element is constructed. It combines with straight member element to Study cable dome structures. The sagging effect of cable is taken into account in the two node cable element. With the aid of updated Lagrangian description and virtual displacement principle, the equilibrium equation of cable dome is established. The incremental method of load is combined with Newton-Raphson method to track the solution A program is desired and an example is studied. The results show that the present method is simple, efficient and accurate. It can be applied to nonlinear analysis of cable dome structures.