The invention discloses an irrigation and fertilization device, system and method. The irrigation and fertilization device comprises a water source pipeline and at least one irrigation and fertilization unit communicated with the water source pipeline; each of the irrigation and fertilization units comprises a fertilizer storage tank, a mixer, a clear water irrigation valve, a fertilizer water irrigation valve and a flowmeter; the clear water irrigation valve and the flowmeter are sequentially communicated, and the inlet end of the clear water irrigation valve is communicated with a water source by using a pipeline; the fertilizer water irrigation valve and the mixer are sequentially communicated, the inlet end of the fertilizer water irrigation valve is communicated with the inlet end ofthe clear water irrigation valve, and the outlet end of the mixer is arranged between the clear water irrigation valve and the flowmeter; and the inlet end of the fertilizer storage tank is communicated with the water source pipeline, and the outlet end of the fertilizer storage tank is communicated with the mixer. The irrigation for soil is controlled by the mixers, the clear water irrigation valves and the fertilizer water irrigation valves, and each of the irrigation and fertilization units is provided with the flowmeter, so that the precise control on the irrigation quantity is realized, diversified irrigation demands are met, and the demand for water and fertilizer management required by soil cultivation is met.