The invention relates to a multi-terminal direct-current power transmission system power coordination method and a control system. The control method comprises a current instruction module, a power consumption module and a direct-current instruction correcting module. For one of rectification stations or inversion stations in the multi-terminal direct-current power transmission system, power consumption is overlaid during calculation of the final current instruction value according to the initial current instruction value. When the power consumption is overlaid to the initial current instruction value corresponding to the rectification station, the power consumption I loss is directly overlaid. When the power consumption is overlaid to the initial current instruction value corresponding to the inversion station, the power consumption I loss is firstly negated and then overlaid. The calculation formula of the power consumption is that I loss=I rectification 1 + I rectification 2 + ... + I rectification m - I inversion 1 - I inversion 2 - ... - I inversion n. According to the invention, coordination control among power can be achieved for the multi-terminal convertor station, and flexible and quick power coordination control is achieved.