Abstract: A set of formulas about the calculation of planar curved beam with uniform section in spatial structure, which is based on the flexibility method, is presented in this paper. The curved beam program segment was set in SAP81. Several quantitative results are worked out, which is coincide very well with the theoretical solution. The comparison of the results by using curved beam element of this paper and a broken line approximation of several straight beam elements shows that the curved beam element is much better than broken line approximation and the later is not acceptable. The implementation of the program segment shows that almost the same computer time was spent for a curved element and a straight one.