Abstract: Aiming at the problem of low utilization rate of agricultural water resources and chemical fertilizer resources in China, the precision operation of water and fertilizer integrated machine in smart agriculture was studied. The water and fertilizer integrated machine was constituted of control system, monitoring system, irrigation and fertilization system, network transmission system and data center. The PSO-fuzzy PID controller was designed to control the EC value and pH value of water and fertilizer solution by combining PSO with PID control algorithm. The control precision of water was improved and the control time was reduced of the water and fertilizer integrated machine. To verify the performance of the water and fertilizer integrated machine, the data acquisition accuracy analysis test and precision operation control test were carried out. The test results show that the data collection is more accurate, and the ratio of water and fertilizer solution could accurately meet the requirement of crop irrigation.