Abstract: Long-distance and large-capacity modular multilevel converter (MMC) is an important scheme to promote renewable energy transmission. With the negative output capability of the full-bridge sub-module (FBSM), the hybrid MMC can realize online bypassing/insertion of valve group and non-blocking DC fault ride-through. Generally, the FBSMs must exceed 50%, resulting in high costs. To improve the economics of hybrid MMC, a hybrid MMC design method with a low proportion of FBSM is proposed. First, with the utilization of sub-module boost capability, the FBSMs proportion in hybrid MMC to satisfy different DC voltage regulation demands is analyzed, and a low FBSMs proportion design principle is proposed. Then, focusing on the over-voltage risk of the reduced number of FBSMs, a fault ride-through strategy is proposed based on sub-module capacitance-voltage control and direct current control. Finally, a discretized calculation method for the transient peak voltage of FBSMs is proposed. Simulation results based on PSCAD reveal that with a 1.25 times FBSM voltage boost, the hybrid MMC with 40% FBSMs can achieve non-blocking fault ride-through, which is similar to the hybrid MMC with 50% FBSMs. The FBSMs are in the safe operating range with a maximum voltage of 1.37 pu, which verifies the feasibility of the proposed method.