The invention belongs to the technical field of 
crop fertilization, and discloses a water and 
fertilizer integrated fertilization method based on a 
crop root growth distribution rule, and the method comprises the following steps: planting crops and reference crops at the same time; calculating 
root system distribution of the reference 
crop through a calculation terminal, generating different soil 
layers along a vertical line direction through 
simulation, and calculating water and 
fertilizer proportions of the different soil 
layers; detecting 
root system distribution conditions of reference crops in different soil 
layers through a detection device; burying an infiltrating 
irrigation pipeline in the infiltrating 
irrigation pit by taking the crop stalk as a circle center; mixing the crop 
fertilizer with water to obtain a liquid fertilizer; the 
irrigation water mixed with the liquid fertilizer flows into the soil through the infiltrating irrigation pipeline for fertilization, and the flow of the liquid fertilizer output by the infiltrating irrigation pipeline is controlled according to the three-dimensional fertilization proportion control model. According to the invention, the 
root system distribution of the reference crop is calculated through the calculation terminal, so that the water-fertilizer proportion and the infiltrating irrigation time required by crop roots in different soil depths can be accurately determined.