Abstract: To research the vehicle-turnout-bridge dynamical interaction under a high-speed running condition,a dynamic model for a vehicle-turnout-bridge coupling system was established,and the numerical simulation method was applied to analyze the dynamic characteristics of turnout and bridge structures,the running safety and the ride comfort.By taking the vertical and horizontal ratios of deflection to span as the index of bridge rigidity,an analysis and calculation were conducted on six standard spans of continuous girder bridges used most commonly in high-speed railway.Dynamic responses,such as vehicle-bridge vibration acceleration,load reduction rate,derailment coefficient,bridge vibration amplitude and acceleration,were acquired,and the reasonable rigidity of a continuous girder bridge with a span of 24,32,40 or 48 m was determined to be 1/20 000,1/9 000,1/5 000 and 1/3 000 respectively.The research shows that except static analyses should meet the relevant criterions,a dynamic analysis is necessary to specific turnout structures,running conditions and bridge structures.