In　order　to　select　reasonable　turnout　plane　alignment　and　switch-rail　cutting　mode,　a　vehicle-turnout　dynamic　coupling　model　was　established　based　on　wheel-rail　system　dynamic　theory.　The　wheel-rail　system　dynamic　responses　of　turnouts　with　various　plane　alignments　were　calculated　and　the　relationship　of　train　speeds　and　dynamic　responses　were　analyzed.　Taking　No.18　turnout　as　an　example,　the　feasibility　of　this　selection　method　was　verified.　Results　shows　that　turnout　plane　alignment　design　should　take　alignment　parameters　of　turnout　branch　and　curved　switch　cutting　mode　into　account　to　ensure　system　dynamic　stability　when　train　passes　through　the　diverging　track　in　the　facing　direction;　the　dynamic　evaluation　method　can　analyze　turnout　branch　alignment　in　terms　of　structure　mechanical　behavior　and　train　running　performance,　and　then　determine　permissible　speed　through　turnout　branch　by　reference　to　the　change　of　system　dynamic　responses　with　various　speed　through　turnout;　for　No.18　turnout,　train　running　performance　and　passing　speed　can　be　improved　by　adding　curve　radius　of　turnout　branch　or　using　composite　circular　alignment　with　greater　front　curve　radius;　the　switch　blade　with　the　line　type　of　semi-tangent　curve　or　semi-secant　curve　is　fit　for　No.18　turnout,　the　robustness　of　switch　blade　with　separation-semi-tangent　line　type　is　better,　and　the　line　type　should　be　one　of　the　main　cutting　mode　for　switch　rail.　©　2017,　Editorial　Board　of　Journal　of　Huazhong　University　of　Science　and　Technology.　All　right　reserved.