Provided in the present invention is a direct current power grid voltage control method, dividing control of a direct current power grid voltage into three processes, namely natural voltage regulation, first voltage regulation and second voltage regulation; the converter stations in the direct current power grid are divided into three types, namely power regulation converter stations, auxiliary voltage regulation converter stations, and voltage regulation converter stations, on the basis of whether the converter station has a voltage regulation capacity, the power regulation converter stations operating in a fixed power control mode, the voltage regulation converter stations operating in a fixed voltage control mode or an auxiliary voltage control mode, and the auxiliary voltage control converter stations operating in the auxiliary voltage control mode; all the converter stations in the direct current power grid participate in natural voltage regulation, the auxiliary voltage regulation converter stations and the voltage regulation converter stations participate in first voltage regulation, and the voltage regulation converter stations participate in second voltage regulation; by means of a combination of the three voltage regulation processes, accurate control of the direct current voltage can be implemented in a steady state, and direct current voltage change can be suppressed in a transient state.