In recent years, as power electronic technology and devices have developed and updated, flexible direct current transmission technology has emerged. Compared with traditional two-level and three-level converters, the Modular Multilevel Converter (MMC), with advantages like modularity, low loss, low component stress, and low harmonic content, is widely used in flexible DC transmission systems. The modulation strategy of MMC has a direct influence on its performance, so this paper studies the influence of two different modulation strategies on the performance of MMC. At present, the commonly used modulation strategies for MMC in DC transmission include nearest level modulation and phase shifted carriers modulation. Therefore, this paper adopts these two modulation strategies to simulate MMC under certain operating conditions in a Matlab/Simulink environment, and then analyzes the characteristics of the two modulation strategies. Finally, it is concluded that different modulation strategies should be adopted under different requirements, which provides certain guiding significance for the selection of MMC modulation strategies under different performance requirements.