With the continuous development of power electronic technology toward the high voltage and high-power conversion, the Modular Multilevel Converter (MMC) has attracted research attention. Since a large number of capacitors, voltage balancing problem becomes one of the key technologies of the MMC. To resolve the voltage balancing problem, this paper presents a novel voltage balancing modulation scheme, which control the instantaneous power of each sub-module timely by adjusting carriers offset in PWM, and the respective capacitor voltage could be stabilized at a set value. Simulation results based on MATLAB / SIMULINK environment are provided to testify to the effectiveness of the proposed method.