A Z-shaft integrating the storage, mixing and extrusion of materials, the Z-shaft comprising a vertically movable storage bin (10), and a vertical movement unit (20) connected to the vertically movable storage bin (10). The vertical movement unit (20) can drive the vertically movable storage bin (10) to move vertically. The vertically movable storage bin (10) is used for storing raw printing materials, a printing nozzle (30) connected to the vertically movable storage bin (10) is arranged at the bottom of the vertically movable storage bin (10), and the vertically movable storage bin (10) is connected to the printing nozzle (30) by means of a mixing unit. An existing shaft which moves in a vertical direction is replaced with the vertically movable storage bin (10), such that the printing nozzle (30) can be directly in communication with the vertically movable storage bin (10), and there is no need for a pipe to connect the printing nozzle (30) and the vertically movable storage bin (10). Further provided is a 3D building printer, which comprises a horizontally movable platform and the Z-shaft that is arranged on the horizontally movable platform and integrates the storage, mixing and extrusion of materials. In the 3D building printer, a relay storage bin does not need to be erected at a high altitude, and thus, the problems of pipe blockage and cleaning are solved.