The invention relates to a process method for in-dock oil putting washing of a hydraulic pipeline of a roll-on / roll-off facility of a container roll-on / roll-off ship. The method includes the following steps that S1, a pipe to be subject to oil putting is pre-treated; S2, oil putting equipment is checked and washed; S3, the hydraulic pipeline is installed; S4, oil putting of the hydraulic pipeline is carried out; and S5, pipeline resetting after oil putting is carried out. According to the method, on the basis of existing equipment layout of the ship, the system pipeline moving direction is used, oil putting equipment such as an oil putting hydraulic unit, a temporary hose, a connector and an oscillator are distributed, it is guaranteed that the oil putting results meet the requirement, layout of the equipment on the ship and a pipe system is sufficiently used, the pipe disassembling, assembling and oil putting time is shortened, the oil putting washing period of the hydraulic pipeline is shortened, an in-dock production joints are well used, the in-dock hydraulic pipeline oil putting washing task is completed, and sufficient time is guaranteed for follow-up equipment debugging.