The invention discloses a large greenhouse wireless monitoring device comprising a light intensity detection module, a temperature detection module, a humidity detection module, an A/D converter, a memory, an intelligent power supply, a core controller, a display, a Zigbee communication module, a timer and an alarm. According to the large greenhouse wireless monitoring device, the sensor technology is adopted, analog signals output by a sensor are converted by a signal processing chip into machine speech which can be identified by a single chip microcomputer and are then output, and the single chip microcomputer processes the transmitted data to complete adjustment of the light intensity, temperature and humidity inside a greenhouse, and finally, intelligent adjustment of the greenhouse is realized. Moreover, the device is powered by the intelligent power supply, electric energy in the circuit is stored in a storage battery, a thyristor switches power supply as an electric power switching element, uninterrupted power supply to the microcomputer can be maintained, and stable operation of the whole system is ensured.