The modulation strategy plays a vital role in the stable operation of a modular multilevel converter (MMC). Aided at the high computational complexity when applying the space vector modulation (SVM) strategy to the MMC, a simplified SVM control strategy is proposed in this paper. First, submodules (SMs) are grouped to form subunits, and the three-level SVM is exploited to control each subunit. Second, the sampling times of adjacent subunits are staggered evenly to achieve multi-level output from the MMC and reduce the harmonic content in output voltage and current. Finally, the capacitor voltage sorting strategy is combined to flexibly control the SMs, thus ensuring a balance between capacitor voltages of SMs. The modulation strategy proposed in this paper can be easily implemented in the topology of an MMC with more SMs, and it also has a low computational complexity and a high control flexibility. Experimental results verify the feasibility and effectiveness of the proposed method.