Metro　construction　is　normally　carried　out　in　complex　engineering　geological　environment,　so　it　can　generate　various　risk　events.　In　the　process　of　metro　construction,　a　scientific　risk　dynamic　analysis　is　indispensable　to　reduce　and　control　risks.　In　order　to　analyze　the　risk　in　metro　construction　more　scientifically　and　reasonably,　in　this　study,　a　new　risk　dynamic　analysis　method　for　metro　construction　is　proposed　using　statistical　process　control.　The　method　can　analyse　the　risk　level　according　to　the　process＇s　capacity　index　and　identify　the　characteristics　of　risk　variation　according　to　the　statistical　control　chart.　The　risk　level　and　the　characteristic　of　risks　may　vary　with　dynamical　updating　of　monitoring　data,　so　the　conclusion　of　risk　evaluation　for　a　time　interval　can　be　drawn　and　corresponding　safety　measures　can　be　ascertained.　The　method　ushers　statistical　process　control,　so　the　random　factors　in　risk　evolution　can　be　considered　fully.　Then,　the　method　is　applied　to　the　risk　analysis　of　shield　construction　under　the　Beijing-Tianjin　intercity　railway　in　Beijing　Metro　Line　8,　a　typical　risk　problem　in　the　traffic　construction.　The　variation　of　the　risk　level　and　the　characteristic　of　risks　can　be　evaluated　reasonably　because　the　dynamical　randomness　is　considered.　Moreover,　whether　risk　control　measures　should　be　taken　and　what　the　effective　measures　are　can　be　ascertained　explicitly.