Modular multi-level inverter (MMC) is modular in design, and able to realize flexible changes in the levels of voltage and power with adjusting the number of sub-module series, and its universal sub-module such as half-bridge, full-bridge structure sub-module has two voltage levels of 0 and 1 to output. This paper proposes a new scheme of sub-module topology for modular multi-level converter, and explains correlative operation principle. The sub-module in the new scheme can output three voltage levels of 0, 1 and 2, and thus in comparison with the original half-bridge structure, for the same output level number, the new topology can save up to 25% of the IGBT, and reduce the total number of sub-modules and the footprint of the converter station. Proposing the corresponding capacitor voltage modulation strategy, the paper does a successful application of the nearest level modulation strategy to the new topology, An NLM based Double-end 11 levels of MMC-HVDC transmission system is set up in the PSCAD simulation environment, and its simulation results show that sub-module capacitor, DC voltage and harmonic are all in agreement with the re-quirements, verifying the correctness and validity of the proposed topology and control strategy.