Abstract: With the rapid development of high-speed railway in China, CRTSⅠdouble-block ballastless track structure is adopted widely. When CRTSⅠdouble-block ballastless track is laid on a line whose temperature changes significantly, there could be a serious problem that the structure is cracking and arching up as the track is a continuous structure. In order to adapt to the conditions of large temperature span and large temperature difference of Lanzhou-Xinjiang second-line, the track slab is considered as the unit slab, with dowel steel being installed at expansion joint, which ensures the vertical and lateral stability of the track structure. The stress and deformation of the rail structure with different numbers of dowel steel are calculated in this paper using finite element method to study the force properties of dowel steel and determine its optimum number. It is suggested that the dowel steel should be not less than 4 in one unit of the rail structure.