The invention discloses a single-pole type hydraulic driving fertilizing device, which mainly comprises a driving cavity body, a main water inlet pipe, a first water inlet pipe, a second water inlet pipe, a first water outlet pipe, a second water outlet pipe, a main water outlet pipe, a moving piston, a control rod, and a fertilizer sucking mechanism; the moving piston is hydraulically driven to vertically and repeatedly move so as to drive the fertilizer sucking mechanism to work, thus the fertilizer sucking mechanism can absorb the fluid fertilizer; the fluid fertilizer is discharged to a main pipeline of an irrigation system through the main water outlet pipe to mix with the irrigation water, and then enters the field through the irrigation system, thereby reaching the purpose of water-fertilizer integrated fertilization. The hydraulic driving part and the fertilization ratio adjusting part are very simple in structure, and are not required to drive by additional power; the single-pole type hydraulic driving fertilizing device is easy to realize automation and free adjustment of fertilizer concentration; besides, the using scale is enlarged, and the labor intensity is reduced.