The invention provides a water, fertilizer and pesticide integrated self-diagnosis irrigation expert system control device which comprises a sensor input circuit, an electromagnetic valve fault detection circuit, a proportional valve driving circuit, an MCU1, an SD memory circuit, an MCU2, an MCU3, a GPRS DTU module, an interface chip 8255 and a memory 6116, wherein a control port of the sensor input circuit is connected with a P3 port of the MCU1, and a D/A port of the sensor input circuit is connected with the proportional valve driving circuit; and the MCU1 is a master controller, a serial port A of the MCU1 is connected with a serial port A of the MCU2, a serial port B of the MCU1 is connected with a serial port B of the MCU3, the MCU1 is also connected with the SD memory circuit, a serial port B of the MCU2 is connected with the GPRS DTU module so as to carry out wireless data communication, and a serial port A of the MCU3 is connected with the serial port B of the MCU2 so as to be used as a communication backup interface. The device provided by the invention realizes spray of fertilizers and pesticides and realizes automation of agricultural management; the three MCU systems are adopted to realize control accuracy and are matched with the shared memory to realize information exchange; and the system performs self-diagnosis and localization of faults, and data communication adopts a key data header so as to guarantee the confidentiality and safety of the data communication.