Research conclusions：(1) Compared with the standard code for the ballastless track of high - speed railway in China， the thicknesses of the bedding surface and bottom of the railways built with the UIC and the French high - speed railway code are thinner, but the compactness is over high. (2) When the QS2 or QS3 grade filling material is used, it can meet the requirement of the Chinas high - speed railway standard，but when the Qsl grade filling material is used, it can not meet the the Chinese standard unless the material is improved- (3) For the treatment of the transition section, the requirement of the Chinese standard is low, but it can be reinforced by enhancing the stiffness of some parts of the bedding. (4) The settlement control standard for the subgrade designed and built with the French experience is more concrete and more strict than the UIC and is the basically same as the Chinese standard. The gap between the France and China can be filled by prolonging the resting time of the embankment or by over filling and compressing.(5) According to the above comparison and the surveys results of the subgrade bedding，subgrade，foundation and transition section, the areas that do not meet the laying requirement can be reinforced by taking measures of refilling, strong compacting，grouting and using the CFG pile and pile - slab structure，and those that meet the laying requirement can be directly used. (6) This research result can provide the reference to laying the ballastless track on the existing subgrade built with the UIC and the French standard and laying the ballastless track on the existing subgrade in China.