The invention relates to a direct current transmission system, in particular to a method for making a high-voltage side group valve put into operation and go out of operation, wherein the method meets the requirements for transmission reliability and availability rate of an ultra high voltage direct current transmission project. The method for making the high-voltage side group valve put into operation includes the following steps that after an ultra high voltage direct current transmission system receives an instruction of putting into operation, a rectifying side is unlocked in advance of an inverting side; after receiving the unlocking instruction, a pole control system of the rectifying side immediately sends out an instruction for separating a high-speed bypass switch; next, the contact separating process of the high-speed bypass switch and the like are performed. The method the control sequence logistic of achieving operation of a low-voltage side group valve in series-connection group valves of the ultra high voltage direct current transmission project and making the high-voltage side group valve put into operation/ go out of operation, the sequential control logistic is clear and facilitates project achievement, the actual requirements of the ultra high voltage direct current transmission project are met, and meanwhile the reliability and the availability rate of the ultra high voltage direct current transmission system can be improved.