Vertical shaft downward shield construction method and device

The invention relates to a vertical shaft downward shield construction method and device, and the vertical shaft downward shield construction method comprises the following steps: manufacturing a wellhead ring beam; a vertical shaft bottom plate is built, a working bin is formed, and an excavating device and a slag conveying device are installed; a soil body is excavated downwards through an excavating device, when downward excavation reaches the preset height, a top ring structure is built, a ring pipe joint is assembled at the bottom of the top ring structure, and a pushing oil cylinder is installed on the top face of a vertical shaft bottom plate; the pushing oil cylinder at the position, corresponding to the to-be-assembled position, of one new duct piece is retracted, and after the new duct piece is conveyed to the to-be-assembled position, the duct piece is pushed and pressed tightly through the pushing oil cylinder till assembling of a new annular pipe joint is completed in sequence; and continuously e