Abstract: Dual three-phase permanent magnet synchronous motors (PMSM) are suitable for high-power traction drive systems. However, the systems are required to operate under low switching-to-fundamental ratio conditions. At this point, the proportion of current ripple increases, decreasing the current quality and affecting the output efficiency. Therefore, this paper proposes the variable switching sequence modulation strategy considering current ripple suppression at low switching-to-fundamental ratio. First, the formula for calculating the current ripple of dual three-phase PMSM is derived, and the current ripple of four-vector modulation strategy and three-phase decomposition modulation strategy is compared. After that, the three-phase decomposition modulation strategy is adopted, and the switching sequences are adjusted to reduce the current ripple peak by dispersing the vector action time. Furthermore, the modulation strategies are switched based on sector subdivision to maintain the small value of current ripple throughout the entire fundamental period of the current. Experimental results show that the proposed method can improve the sine of current, and reduce current ripple as well as motor losses.