In order to ensure the safety of transportation, the reliability of the drive hydraulic system group of two transport vehicles combined transportationare studied. The key of the safe transportation is synchronous control, which requires high reliability of the drive hydraulic system group and control system. It is necessary to study the life prediction and reliability growth of drive hydraulic system group. The reliability of the drive hydraulic system group of the two transport vehicles is taken as the research object. Firstly, the reliability model of one transport vehicle is studied, and the reliability block diagram model is established for the drive hydraulic system. At the same time, the corresponding mathematical model of reliability is established. The reliability curve of the drive hydraulic system is obtained by using the MATLAB software. On this basis, the reliability of the combined vehicles drive hydraulic system group is also obtained. Based on the analysis of the drive asynchronous problems in the engineering practice, the fault tree of the drive hydraulic system failure is established. The quantitative and qualitative analysis is carried out for the fault tree, and the weak links of the drive hydraulic system are found out. The prevention of the failure can be considered in the design process, and the design level of the system will be improved. The method can be used to improve the reliability of the hydraulic system group of multivehiclecombined transportation.