The invention relates to a full-drift-diameter hydraulic-drive layering liquid injection and fracturing device and method. According to the technical scheme, an upper connector and a lower connector are connected through a center pipe, a sealing piston, a constant pressure switch, a uniflow sliding way body, a rotating ring pressing cap and a rotating ring from a movement body, the constant pressure switch is arranged between the sealing piston and the center pipe, the lower portion of the constant pressure switch is connected with the uniflow sliding way body, the lower portion of the uniflow sliding way body is provided with the rotating ring, the upper portion of the rotating ring is connected with the center pipe through the rotating ring pressing cap, the rotating ring rotates around the center pipe, the lower portion of the movement body is provided with an energy storage mechanism, the bottom of the energy storage mechanism is connected with an energy storage pad, the lower portion of the energy storage pad is connected with a pressure adjusting ring, the pressure adjusting ring is connected with a sealing cylinder sleeve through a positioning pin, and a rail is arranged in the middle of the center pipe. The full-drift-diameter hydraulic-drive layering liquid injection and fracturing device and method have the advantages that the process is simple, it is avoided that multiple layers of pipe columns are placed into a well, layering liquid injection is clear, pressuring is conducted from top to bottom, the device reaches the required water injection layers, and multi-layer connection water injection is achieved; the adjustable function and closable function in the downhole water injection work are achieved, layering water injection is achieved, and meanwhile joint injection can be achieved.