Abstract: This paper proposes a hybrid electric propulsion system based on BDS. The two main power sources of the diesel engine and the electric motor adopt PTH driving mode. The fuel and electric energy are used to provide propulsion power. Different navigation areas and speed can be selected according to BDS Power source output. After fuel economy and benefit analysis, compared with the traditional propulsion system, the application of BDS-based hybrid propulsion system reduces the operating cost of official ships by 26％, and the increased initial construction investment cost of tana business ship can be recovered within 3 years; Comprehensive fuel saving of 15％ to 20％, the initial construction investment cost can be recovered within 4 years through the fuel saving method. The hybrid system based on BDS can increase propulsion redundancy, improve ship safety, and has good effects of energy saving and emission reduction and saving operating costs.