This paper presents a carrier-based modulation strategy for 3×1-modular matrix converters (MC) to achieve zero common mode voltage (CMV). A geometric method is introduced to determine the range of the modulation signals. Due to the nonzero CMV during the commutation time with the traditional four-step current-based commutation method, a modified four-step current-based commutation method is presented. Additionally, to expand the modulation strategy to multi-modular MC properly, the phase-shifted (PS) method is applied. The 3∗3-modular MC is built on Matlab/Simulink platform to verify the validity of the proposed modulation strategy.