The invention relates to a double 12-pulse valve bank coordinated-control method for an ultra-high voltage direct-current transmission system. The method is realized in a way that: two valve banks at each pole are connected in series, one ends are connected with each other, and the other ends are respectively connected to an polar high voltage bus and a polar neutral bus; the pole control system is divided into a dipole\pole control layer and a valve bank control layer, the valve bank control layer realizes trigger control on the high-voltage valve bank and the low-voltage valve bank, each valve bank control only collects the respective 12-pulse valve bank conversion flow bus voltage as the synchronous voltage of the trigger pulse, the trigger angle of the two 12-pulse valve banks in series can be adjusted to maintain the direct-current current and the direct current voltage, and the trigger angle between the valve banks in series can be coordinated and controlled to realize balanced operation of the valve banks in series; and the dipole\pole control layer generates a current command and simultaneously transmits the current command to high voltage and low voltage, i.e. master-slave valve bank control. The invention solves the problems of trigger angle deviation of high-voltage valve bank and low-voltage bank in series, and unbalanced voltage distribution caused by competitive control between valve banks in series, measuring errors and other factors.