Abstract: Aiming at the problem of low efficiency and low utilization rate of water and fertilizer in the traditional irrigation and fertilization methods, the structure of water and fertilizer based on mathematical model was designed and optimized. The water and fertilizer integrated machine was constituted of data acquisition system, irrigation and fertilization system, automatic control system and control center. To realize precise fertilization and irrigation, the structure of Venturi fertilizer absorber was optimized by the method of mathematical model. And the control algorithm combining fuzzy control and grey prediction was used to predict irrigation. The comparative test of fertilizer absorption performance and irrigation test were carried out. The test result show that the structure of the water and fertilizer integrated machine is reasonable, and the accurate irrigation can be realized.