This article addresses the issue of insufficient research on the safety of high-voltage wiring harnesses in collision scenarios of new energy vehicles and proposes a safety determination method that integrates multi-scale tests and simulation analysis. Firstly，by layer-by-layer analysis of the mechanical properties of high-voltage wire harness materials，a two-component equivalent finite element model is established；secondly，a dedicated extrusion testing device is designed to test the wire harnesses protected by corrugated tubes and anti-cutting cloth. Finally，by comparing the vehicle collision simulation and test thresholds，a criterion system with a 10% safety margin was established to provide a reference for the safety design of high-voltage wiring harnesses.