Generally speaking, the systems of deep-sea mining consist of a mining support vessel at surface, a seafloor collector on seabed, and a vertical transport system connecting them. The traditional vertical transport systems of deep-sea mining, which are either hydraulic or airlift, have low efficiency and high cost. In this paper, a kind of buoyancy vertical transport system of deep-sea mining is briefly described. Unlike the traditional ones, this new transport system is based on buoyancy and gravity, which could work in arbitrary depth of water but cheaper.