Abstract: The temperature measurement of track slab was carried out for two days near Xiaoganbei Railway Station. The warping of track slab under overall temperature change and temperature gradient was analyzed with the temperature field of track slab simulated by applying temperature load on the nodes. By applying the vertical rail displacements caused by the warping of track slab as the additional rail irregularities, the dynamic analysis model was established to analyze the dynamic performance of the train-track system, based on which the running safety of high-speed train in the warping section of track slab was calculated. The results show that the temperature warping of CRTSII slab ballastless track is mainly influenced by the temperature gradient and the difference between initial temperature and surface temperature. Larger temperature gradient causes larger temperature warping. Under the same temperature gradient, the temperature warping is reduced with the decrease of the difference between initial temperature and surface temperature. The dynamic responses are larger, especially the accelerations of rail and track slab when considering the additional rail irregularities caused by the temperature warping of track slab, which leads to degraded running safety indexes.