Abstract: To address the issues in insulation detection for new energy charging systems-including susceptibility of sampling results to external electromagnetic interference, instability of single insulation detection results, and poor insulation accuracy-this paper proposes an improved insulation detection algorithm. The algorithm constructs an overdetermined system of equations for insulation detection parameters during the detection step to fit the insulation results. experimental results show that, compared with traditional single calculations, the impact of external electromagnetic interference and sampling errors on insulation accuracy is reduced, achieving an improvement in insulation accuracy of over 10% in engineering applications.