The invention discloses a method for allowing a multi-end flexible direct-current power transmission system to conduct charged access through an isolation switch. The method is used for enabling the multi-end flexible direct-current power transmission system to have access to other ends under the condition that the multi-end flexible direct-current power transmission system is not powered off. According to the method, stability of the multi-end flexible direct-current power transmission system is ensured in the running process, and power transmission economical efficiency is improved by using the isolation switch to replace direct-current circuit breakers. The end to which the system is to have access and from which the system is isolated tracks the direct-current voltage of a running circuit when the single station runs stably, and ensures that the voltage difference between the two sides of the isolation switch is within a permitted range through fixed direct-current voltage control. The amplitude of the direct-current target value, of the end to which the system is to have access, for controlling the direct-current voltage is limited, limited direct-current voltage control capacity is provided, and it is ensured that two fixed direct-current voltage converter stations which include the main converter station and the station to which the system is to have access exist at the same time and do not produce severe voltage oscillation when connected into a grid in the delayed time between switching on of the isolation switch and switching of the control mode. The method is convenient to operate, stable in running and good in economical efficiency, and has guiding significance in charged access of the converter stations of the multi-end flexible direct-current power transmission system.