Abstract: This essay introduces what the Plat Screen Door(PSD) system consists of,analyses the reasons of why PSD system not only need grounding for lightning but also need installment of insulated equipotential.It proposes the method of PSD system insulated installment and specific measures of lightning protection,whilst,presents the relevance of lightning protection and insulation of PSD system,in the aspect of safeguarding the Metro’s working.It provides references for professional staff who attend design and construction of metro project,and at the same time,it provides reliances for lightning test of metro project.