A central-pivot sprinkler and a controllable variable spray gun for the central-pivot sprinkler. The controllable variable spray gun comprises a spray gun main body (2), a booster pump (7), and a spray gun connecting pipe (16). A water inlet of the booster pump (7) is communicated with a sprinkler pipe (15) of the central-pivot sprinkler. A water outlet of the booster pump (7) is connected to a water inlet of the spray gun main body (2) by means of the spray gun connecting pipe (16). The forepart of the spray gun main body (2) is provided with a spray nozzle (12). The tail portion of the spray gun main body (2) can be mounted at the end of a crossing-body (1) of the central-pivot sprinkler by means of a spray gun horizontal-rotation mechanism. A spray angle of the spray gun main body (2) is automatically adjusted by means of a preset program, so that four corners of a square plot can be evenly irrigated, accordingly the utilization rate of land is improved, and the landform around the plot is not affected.
