The invention belongs to the field of power electronics, and particularly relates to a modulation method for reducing common-mode voltage of a three-phase pulse-width modulation (PWM) converter. The modulation method is characterized in that three nonadjacent nonzero basic space vectors are used for synthesizing a target vector, and is further characterized in that two comparison value counting modules are adopted to generate control pulse, and the counting modules are different in counting mode. Counting modes of the comparison value counting modules used for generation of out-phase bridge arm control pulse in the same sector of voltage commands are different, and in the different sectors, the counting modes of the comparison value counting modules used by the same-phrase bridge arm are also different. The modulation method has a good common-mode voltage restraining effect, the common-mode voltage maximum peak is one-sixth of direct current bus voltage, and therefore common-mode currents can be effectively reduced when the modulation method is applied to fields of photovoltaic power stations, motor drive and charging stations.