Abstract: Flexible barriers have been widely used in mountainous areas for mitigation of rockfalls. In view of the lack of an applicable engineering design method, we proposed a nonlinear static design method for flexible rockfall barriers firstly. In the method, the discrimination criterion for loading completion is defined as the internal energy of the structure equals to the design nominal protection level. Then, we carried out nonlinear dynamic analyses of 8 flexible rockfall barriers based on LS-DYNA. The energy levels of these flexible barriers ranged from 250 kJ to 5000 kJ. We clarified the distribution of impact load and relative loading coefficient. On this basis, we proposed the load modes for nonlinear static design of flexible rockfall barriers with different energy levels. Next, in order to simulate the special characteristics in flexible barriers, we developed a non-linear energy dissipation element and a sliding cable element. The non-linear energy dissipation element combines a cable element with a spring element to simulate energy dissipation devices. The sliding cable element consists of multi-segment cable elements to simulate sliding boundaries and ring nets. Finally, we carried out back analyses of full-scale impact tests of a ring net, as well as a three-span flexible rockfall barrier with the nominal protection energy level of 3500 kJ. The results show the nonlinear static design method proposed in the paper is effective for flexible rockfall barriers design.