Locally resonant metamaterials (LMs) have received extensive attention for their extraordinary physical properties, while less study on their application in the field of collision exists. In this paper, we extend the application of LMs to field of structural collision and achieve the mitigation of impact force based on their negative effective mass property. We also propose a three-resonator metamaterial (TRM) to enhance the attenuation effect of impact stress waves. Based on the theoretical analysis, the width of the negative effective mass frequency regions of TRM is wider than those of single-resonator metamaterial (SRM) and dual-resonator metamaterial (DRM). In numerical cases, the superior performance of TRM is also validated based on the impact wave model and the non-convex multi-corner thin-walled column crash model compared with SRM and DRM. The multi-objective optimization analyses are also conducted to enhance the performance of TRM with high impact force mitigation, great improvement of vehicle crashworthiness and small LMs mass.