As　a　device　for　time-delay,　clock　mechanism　is　widely　used　in　fuze　safety　and　arming　device,　whose　core　component　is　the　runaway　escapement.　With　the　development　of　artillery　systems,　the　dynamic　environment　during　the　projectile　becomes　more　and　more　complicated.　Recently,　some　shots　misfire　or　premature　explode　during　shooting　process　because　runaway　escapements＇　miswork.　This　paper　utilizes　gear　system＇s　research　results　applied　in　other　fields,　discusses　clock　mechanism＇s　dynamics　problem,　and　uses　ADAMS　to　analyze　runaway　escapement＇s　rigid-flexible　coupling　model.　From　comparing　the　simulation　results　of　multi-rigid　model　and　rigid-flexible　coupling　model,　we　find　that　elastic　deformation　will　affect　runaway　escapement＇s　movement,　even　can　cause　the　whole　device　to　work　abnormally.