Abstract: A two-node curved cable element is presented for nonlinear analysis of cable structures, in which the cable's initial shape of long-span structure is considered. The present method overcomes the disadvantages of two other widely used elements: two-node linear bar element which has low precision and multi-node element which is difficult to computerize for many D.O.F. Based on Updated Lagangian Formulation, the shagness mallix is derived explicitly according to the First Castigliano's Theory. Program has been developed and some examples are analyzed. The results show that the proposed element is reliable and applicable for the analysis of long-span structures, such as cable-stayed towers and tension structures.