The criterion for residual deformation of Substructure of unballasted track on railway passenger dedicated line is extremely strict in order to satisfy the safety and comfort requirements of the high-speed train. Based on new Wuhan(Guangzhou railway passenger dedicated line engineering practice,this paper introuduces the key technologies for the deformation monitoring, data management and analysis system, the prediction method and assessment criterion are put forward to determine the reasonable time of unballasted track laying to guarantee the quality of unballasted track. Some advice provide reference for the ongoing unballasted track on railway passenger dedicated line construction.