Wire ropes are often used in flexible barriers or road engineering to resist lateral impact because of their good reliability, high economy, and construction convenience. However, their application under lateral impact lacks a systematic design approach. In this paper, to ensure the safe use of the structure, the lateral impact test of single wire ropes and wire rope nets is carried out, and the strain, displacement, and acceleration response are analyzed. In addition, the tensile mechanical properties of wire rope strands are determined through static tensile mechanical properties tests, which provide reasonable parameters for the constitutive model used in numerical simulations. Furthermore, considering the influence of wire rope pre-tension ratio, span ratio, and mass ratio, empirical formulas for longitudinal peak tensile force and lateral peak displacement are given. The results show that the wire rope mainly occurs local abrasion at the impact point, fracture, and end connection failure. It is worth noting that when the dimensionless lateral peak displacement (ωm) reaches 0.089, the wire rope breaks. Moreover, according to Lagrange Green’s strain theory, a theoretical calculation formula for the mid-span lateral limit displacement of wire rope under pre-tension is derived and compared with the simulated values of test members. Consequently, according to the damage degree of wire ropes, the damage limit value is determined. Finally, considering the tensile capacity of wire ropes and their displacement responses, a limit state function is proposed to evaluate the damage of existing components or to design new components.