A decision-making method for variable rate irrigation management includes the following steps: S1: sampling a soil from a root zone of a crop in an area controlled by an irrigation sprinkler, and measuring compositions of separates of the sampled soil; S2: managing and dividing the area controlled by the irrigation sprinkler according to an AWC of the soil in the root zone of the crop; S3: constructing an optimized soil moisture sensor network; S4: placing ground-fixed canopy temperature sensors; S5: constructing an optimized airborne canopy temperature sensor network centered on the center pivot; and S6: performing a variable rate irrigation by using the optimized soil moisture sensor network, the fixed canopy temperature sensors, the optimized airborne canopy temperature sensor network and an automatic weather station. The method optimizes the placement and quantity of the soil moisture sensor network and the canopy temperature sensor network to improve the measurement accuracy.