The Bohai Strait cross-sea passage is a long period,large investment construction project. It's an important problem about the investment, financing, and the return on investment (ROI) of the project. This paper,comparative analysis of the existing cross- sea channels at home and abroad, puts forward that Bohai Strait cross-sea channel can take build-operate-transfer (BOT) financing mode. The internal rate of return (IRR) of this project is about 9.63 %, higher than the social discount rate commonly, which indicates that the project has economic feasibility. In terms of revenue, this is a "multi-win" project for the government, public, investors and many other stakeholders.