The performance of passive flexible protective structure includes mechanical performance, energy dissipation performance and deformation performance, but most of the current research is focused on the former two, and only a few scholars have studied its deformation performance. Taking "residual interception height" and "falling rock buffer distance" as the key technical indexes to evaluate the deformation performance of passive flexible protective structures, a new passive flexible rockfall barrier for intercepting and buffering the impact energy of falling rocks is proposed. Based on ANSYS/LS-DYNA, three types of ring net models are established, and the energy consumption and deformation performance of ring net are analyzed from three aspects: maximum energy consumption, residual interception height and falling rock buffer distance. The results show that the ring net with vertical support can effectively reduce the buffer distance of falling rocks and increase the residual interception height of the ring net, but the maximum energy consumption of the ring net has decreased to some extent. Compared with unsupported and double-supported ring nets, single-supported ring nets have the following advantages: the maximum energy consumption ratio is relatively high, it has the function of rapidly attenuating the impact energy of falling rocks under the action of instantaneous impact load, the buffer distance of falling rocks is small, and the stability with the change of impact position is good. Therefore, it is suggested that the single-supported ring net should be preferentially used in rockfall protection projects such as the slope with the rockfall barrier laying position close to the road, the horizontal laying of rockfall barrier in the steep slope and the secondary protection.